Convert react-native-github/Libraries to let/const

Reviewed By: sahrens

Differential Revision: D7956042

fbshipit-source-id: 221851aa311f3cdd6326497352b366048db0a1bb

Libraries/ART/ARTSerializablePath.js

@@ -9,16 +9,16 @@
 
 // TODO: Move this into an ART mode called "serialized" or something
 
-var Class = require('art/core/class.js');
+const Class = require('art/core/class.js');
-var Path = require('art/core/path.js');
+const Path = require('art/core/path.js');
 
-var MOVE_TO = 0;
+const MOVE_TO = 0;
-var CLOSE = 1;
+const CLOSE = 1;
-var LINE_TO = 2;
+const LINE_TO = 2;
-var CURVE_TO = 3;
+const CURVE_TO = 3;
-var ARC = 4;
+const ARC = 4;
 
-var SerializablePath = Class(Path, {
+const SerializablePath = Class(Path, {
 
   initialize: function(path) {
     this.reset();

Libraries/ART/ReactNativeART.js

@@ -7,17 +7,17 @@
  */
 'use strict';
 
-var Color = require('art/core/color');
+const Color = require('art/core/color');
-var Path = require('ARTSerializablePath');
+const Path = require('ARTSerializablePath');
-var Transform = require('art/core/transform');
+const Transform = require('art/core/transform');
 
-var React = require('React');
+const React = require('React');
-var PropTypes = require('prop-types');
+const PropTypes = require('prop-types');
-var ReactNativeViewAttributes = require('ReactNativeViewAttributes');
+const ReactNativeViewAttributes = require('ReactNativeViewAttributes');
 
-var createReactNativeComponentClass = require('createReactNativeComponentClass');
+const createReactNativeComponentClass = require('createReactNativeComponentClass');
-var merge = require('merge');
+const merge = require('merge');
-var invariant = require('fbjs/lib/invariant');
+const invariant = require('fbjs/lib/invariant');
 
 // Diff Helpers
 
@@ -28,7 +28,7 @@ function arrayDiffer(a, b) {
   if (a.length !== b.length) {
     return true;
   }
-  for (var i = 0; i < a.length; i++) {
+  for (let i = 0; i < a.length; i++) {
     if (a[i] !== b[i]) {
       return true;
     }
@@ -62,22 +62,22 @@ function fontAndLinesDiffer(a, b) {
 
 // Native Attributes
 
-var SurfaceViewAttributes = merge(ReactNativeViewAttributes.UIView, {
+const SurfaceViewAttributes = merge(ReactNativeViewAttributes.UIView, {
   // This should contain pixel information such as width, height and
   // resolution to know what kind of buffer needs to be allocated.
   // Currently we rely on UIViews and style to figure that out.
 });
 
-var NodeAttributes = {
+const NodeAttributes = {
   transform: { diff: arrayDiffer },
   opacity: true,
 };
 
-var GroupAttributes = merge(NodeAttributes, {
+const GroupAttributes = merge(NodeAttributes, {
   clipping: { diff: arrayDiffer }
 });
 
-var RenderableAttributes = merge(NodeAttributes, {
+const RenderableAttributes = merge(NodeAttributes, {
   fill: { diff: arrayDiffer },
   stroke: { diff: arrayDiffer },
   strokeWidth: true,
@@ -86,11 +86,11 @@ var RenderableAttributes = merge(NodeAttributes, {
   strokeDash: { diff: arrayDiffer },
 });
 
-var ShapeAttributes = merge(RenderableAttributes, {
+const ShapeAttributes = merge(RenderableAttributes, {
   d: { diff: arrayDiffer },
 });
 
-var TextAttributes = merge(RenderableAttributes, {
+const TextAttributes = merge(RenderableAttributes, {
   alignment: true,
   frame: { diff: fontAndLinesDiffer },
   path: { diff: arrayDiffer }
@@ -98,25 +98,25 @@ var TextAttributes = merge(RenderableAttributes, {
 
 // Native Components
 
-var NativeSurfaceView = createReactNativeComponentClass('ARTSurfaceView',
+const NativeSurfaceView = createReactNativeComponentClass('ARTSurfaceView',
   () => ({
     validAttributes: SurfaceViewAttributes,
     uiViewClassName: 'ARTSurfaceView',
   }));
 
-var NativeGroup = createReactNativeComponentClass('ARTGroup',
+const NativeGroup = createReactNativeComponentClass('ARTGroup',
   () => ({
     validAttributes: GroupAttributes,
     uiViewClassName: 'ARTGroup',
   }));
 
-var NativeShape = createReactNativeComponentClass('ARTShape',
+const NativeShape = createReactNativeComponentClass('ARTShape',
   () => ({
     validAttributes: ShapeAttributes,
     uiViewClassName: 'ARTShape',
   }));
 
-var NativeText = createReactNativeComponentClass('ARTText',
+const NativeText = createReactNativeComponentClass('ARTText',
   () => ({
     validAttributes: TextAttributes,
     uiViewClassName: 'ARTText',
@@ -149,9 +149,9 @@ class Surface extends React.Component {
   }
 
   render() {
-    var props = this.props;
+    const props = this.props;
-    var w = extractNumber(props.width, 0);
+    const w = extractNumber(props.width, 0);
-    var h = extractNumber(props.height, 0);
+    const h = extractNumber(props.height, 0);
     return (
       <NativeSurfaceView style={[props.style, { width: w, height: h }]}>
         {this.props.children}
@@ -172,12 +172,12 @@ function extractNumber(value, defaultValue) {
   return +value;
 }
 
-var pooledTransform = new Transform();
+const pooledTransform = new Transform();
 
 function extractTransform(props) {
-  var scaleX = props.scaleX != null ? props.scaleX :
+  const scaleX = props.scaleX != null ? props.scaleX :
                props.scale != null ? props.scale : 1;
-  var scaleY = props.scaleY != null ? props.scaleY :
+  const scaleY = props.scaleY != null ? props.scaleY :
                props.scale != null ? props.scale : 1;
 
   pooledTransform
@@ -219,7 +219,7 @@ class Group extends React.Component {
   };
 
   render() {
-    var props = this.props;
+    const props = this.props;
     invariant(
       this.context.isInSurface,
       'ART: <Group /> must be a child of a <Surface />'
@@ -236,14 +236,14 @@ class Group extends React.Component {
 
 class ClippingRectangle extends React.Component {
   render() {
-    var props = this.props;
+    const props = this.props;
-    var x = extractNumber(props.x, 0);
+    const x = extractNumber(props.x, 0);
-    var y = extractNumber(props.y, 0);
+    const y = extractNumber(props.y, 0);
-    var w = extractNumber(props.width, 0);
+    const w = extractNumber(props.width, 0);
-    var h = extractNumber(props.height, 0);
+    const h = extractNumber(props.height, 0);
-    var clipping = [x, y, w, h];
+    const clipping = [x, y, w, h];
     // The current clipping API requires x and y to be ignored in the transform
-    var propsExcludingXAndY = merge(props);
+    const propsExcludingXAndY = merge(props);
     delete propsExcludingXAndY.x;
     delete propsExcludingXAndY.y;
     return (
@@ -259,13 +259,13 @@ class ClippingRectangle extends React.Component {
 
 // Renderables
 
-var SOLID_COLOR = 0;
+const SOLID_COLOR = 0;
-var LINEAR_GRADIENT = 1;
+const LINEAR_GRADIENT = 1;
-var RADIAL_GRADIENT = 2;
+const RADIAL_GRADIENT = 2;
-var PATTERN = 3;
+const PATTERN = 3;
 
 function insertColorIntoArray(color, targetArray, atIndex) {
-  var c = new Color(color);
+  const c = new Color(color);
   targetArray[atIndex + 0] = c.red / 255;
   targetArray[atIndex + 1] = c.green / 255;
   targetArray[atIndex + 2] = c.blue / 255;
@@ -273,14 +273,14 @@ function insertColorIntoArray(color, targetArray, atIndex) {
 }
 
 function insertColorsIntoArray(stops, targetArray, atIndex) {
-  var i = 0;
+  let i = 0;
   if ('length' in stops) {
     while (i < stops.length) {
       insertColorIntoArray(stops[i], targetArray, atIndex + i * 4);
       i++;
     }
   } else {
-    for (var offset in stops) {
+    for (const offset in stops) {
       insertColorIntoArray(stops[offset], targetArray, atIndex + i * 4);
       i++;
     }
@@ -289,8 +289,8 @@ function insertColorsIntoArray(stops, targetArray, atIndex) {
 }
 
 function insertOffsetsIntoArray(stops, targetArray, atIndex, multi, reverse) {
-  var offsetNumber;
+  let offsetNumber;
-  var i = 0;
+  let i = 0;
   if ('length' in stops) {
     while (i < stops.length) {
       offsetNumber = i / (stops.length - 1) * multi;
@@ -298,7 +298,7 @@ function insertOffsetsIntoArray(stops, targetArray, atIndex, multi, reverse) {
       i++;
     }
   } else {
-    for (var offsetString in stops) {
+    for (const offsetString in stops) {
       offsetNumber = (+offsetString) * multi;
       targetArray[atIndex + i] = reverse ? 1 - offsetNumber : offsetNumber;
       i++;
@@ -308,21 +308,21 @@ function insertOffsetsIntoArray(stops, targetArray, atIndex, multi, reverse) {
 }
 
 function insertColorStopsIntoArray(stops, targetArray, atIndex) {
-  var lastIndex = insertColorsIntoArray(stops, targetArray, atIndex);
+  const lastIndex = insertColorsIntoArray(stops, targetArray, atIndex);
   insertOffsetsIntoArray(stops, targetArray, lastIndex, 1, false);
 }
 
 function insertDoubleColorStopsIntoArray(stops, targetArray, atIndex) {
-  var lastIndex = insertColorsIntoArray(stops, targetArray, atIndex);
+  let lastIndex = insertColorsIntoArray(stops, targetArray, atIndex);
   lastIndex = insertColorsIntoArray(stops, targetArray, lastIndex);
   lastIndex = insertOffsetsIntoArray(stops, targetArray, lastIndex, 0.5, false);
   insertOffsetsIntoArray(stops, targetArray, lastIndex, 0.5, true);
 }
 
 function applyBoundingBoxToBrushData(brushData, props) {
-  var type = brushData[0];
+  const type = brushData[0];
-  var width = +props.width;
+  const width = +props.width;
-  var height = +props.height;
+  const height = +props.height;
   if (type === LINEAR_GRADIENT) {
     brushData[1] *= width;
     brushData[2] *= height;
@@ -356,7 +356,7 @@ function extractBrush(colorOrBrush, props) {
     }
     return colorOrBrush._brush;
   }
-  var c = new Color(colorOrBrush);
+  const c = new Color(colorOrBrush);
   return [SOLID_COLOR, c.red / 255, c.green / 255, c.blue / 255, c.alpha];
 }
 
@@ -364,7 +364,7 @@ function extractColor(color) {
   if (color == null) {
     return null;
   }
-  var c = new Color(color);
+  const c = new Color(color);
   return [c.red / 255, c.green / 255, c.blue / 255, c.alpha];
 }
 
@@ -391,9 +391,9 @@ function extractStrokeJoin(strokeJoin) {
 
 class Shape extends React.Component {
   render() {
-    var props = this.props;
+    const props = this.props;
-    var path = props.d || childrenAsString(props.children);
+    const path = props.d || childrenAsString(props.children);
-    var d = (path instanceof Path ? path : new Path(path)).toJSON();
+    const d = (path instanceof Path ? path : new Path(path)).toJSON();
     return (
       <NativeShape
         fill={extractBrush(props.fill, props)}
@@ -413,10 +413,10 @@ class Shape extends React.Component {
 
 // Text
 
-var cachedFontObjectsFromString = {};
+const cachedFontObjectsFromString = {};
 
-var fontFamilyPrefix = /^[\s"']*/;
+const fontFamilyPrefix = /^[\s"']*/;
-var fontFamilySuffix = /[\s"']*$/;
+const fontFamilySuffix = /[\s"']*$/;
 
 function extractSingleFontFamily(fontFamilyString) {
   // ART on the web allows for multiple font-families to be specified.
@@ -431,15 +431,15 @@ function parseFontString(font) {
   if (cachedFontObjectsFromString.hasOwnProperty(font)) {
     return cachedFontObjectsFromString[font];
   }
-  var regexp = /^\s*((?:(?:normal|bold|italic)\s+)*)(?:(\d+(?:\.\d+)?)[ptexm\%]*(?:\s*\/.*?)?\s+)?\s*\"?([^\"]*)/i;
+  const regexp = /^\s*((?:(?:normal|bold|italic)\s+)*)(?:(\d+(?:\.\d+)?)[ptexm\%]*(?:\s*\/.*?)?\s+)?\s*\"?([^\"]*)/i;
-  var match = regexp.exec(font);
+  const match = regexp.exec(font);
   if (!match) {
     return null;
   }
-  var fontFamily = extractSingleFontFamily(match[3]);
+  const fontFamily = extractSingleFontFamily(match[3]);
-  var fontSize = +match[2] || 12;
+  const fontSize = +match[2] || 12;
-  var isBold = /bold/.exec(match[1]);
+  const isBold = /bold/.exec(match[1]);
-  var isItalic = /italic/.exec(match[1]);
+  const isItalic = /italic/.exec(match[1]);
   cachedFontObjectsFromString[font] = {
     fontFamily: fontFamily,
     fontSize: fontSize,
@@ -456,9 +456,9 @@ function extractFont(font) {
   if (typeof font === 'string') {
     return parseFontString(font);
   }
-  var fontFamily = extractSingleFontFamily(font.fontFamily);
+  const fontFamily = extractSingleFontFamily(font.fontFamily);
-  var fontSize = +font.fontSize || 12;
+  const fontSize = +font.fontSize || 12;
-  var fontWeight = font.fontWeight != null ? font.fontWeight.toString() : '400';
+  const fontWeight = font.fontWeight != null ? font.fontWeight.toString() : '400';
   return {
     // Normalize
     fontFamily: fontFamily,
@@ -468,7 +468,7 @@ function extractFont(font) {
   };
 }
 
-var newLine = /\n/g;
+const newLine = /\n/g;
 function extractFontAndLines(font, text) {
   return { font: extractFont(font), lines: text.split(newLine) };
 }
@@ -486,10 +486,10 @@ function extractAlignment(alignment) {
 
 class Text extends React.Component {
   render() {
-    var props = this.props;
+    const props = this.props;
-    var path = props.path;
+    const path = props.path;
-    var textPath = path ? (path instanceof Path ? path : new Path(path)).toJSON() : null;
+    const textPath = path ? (path instanceof Path ? path : new Path(path)).toJSON() : null;
-    var textFrame = extractFontAndLines(
+    const textFrame = extractFontAndLines(
       props.font,
       childrenAsString(props.children)
     );
@@ -515,14 +515,14 @@ class Text extends React.Component {
 // Declarative fill type objects - API design not finalized
 
 function LinearGradient(stops, x1, y1, x2, y2) {
-  var type = LINEAR_GRADIENT;
+  const type = LINEAR_GRADIENT;
 
   if (arguments.length < 5) {
-    var angle = ((x1 == null) ? 270 : x1) * Math.PI / 180;
+    const angle = ((x1 == null) ? 270 : x1) * Math.PI / 180;
 
-    var x = Math.cos(angle);
+    let x = Math.cos(angle);
-    var y = -Math.sin(angle);
+    let y = -Math.sin(angle);
-    var l = (Math.abs(x) + Math.abs(y)) / 2;
+    const l = (Math.abs(x) + Math.abs(y)) / 2;
 
     x *= l; y *= l;
 
@@ -535,7 +535,7 @@ function LinearGradient(stops, x1, y1, x2, y2) {
     this._bb = false;
   }
 
-  var brushData = [type, +x1, +y1, +x2, +y2];
+  const brushData = [type, +x1, +y1, +x2, +y2];
   insertColorStopsIntoArray(stops, brushData, 5);
   this._brush = brushData;
 }
@@ -562,7 +562,7 @@ function RadialGradient(stops, fx, fy, rx, ry, cx, cy) {
   // To simulate this we render the gradient twice as large and add double
   // color stops. Ideally this API would become more restrictive so that this
   // extra work isn't needed.
-  var brushData = [RADIAL_GRADIENT, +fx, +fy, +rx * 2, +ry * 2, +cx, +cy];
+  const brushData = [RADIAL_GRADIENT, +fx, +fy, +rx * 2, +ry * 2, +cx, +cy];
   insertDoubleColorStopsIntoArray(stops, brushData, 7);
   this._brush = brushData;
 }
@@ -571,7 +571,7 @@ function Pattern(url, width, height, left, top) {
   this._brush = [PATTERN, url, +left || 0, +top || 0, +width, +height];
 }
 
-var ReactART = {
+const ReactART = {
   LinearGradient: LinearGradient,
   RadialGradient: RadialGradient,
   Pattern: Pattern,

Libraries/Alert/Alert.js

@@ -68,7 +68,7 @@ class AlertAndroid {
     buttons?: Buttons,
     options?: Options,
   ): void {
-    var config = {
+    let config = {
       title: title || '',
       message: message || '',
     };
@@ -78,10 +78,10 @@ class AlertAndroid {
     }
     // At most three buttons (neutral, negative, positive). Ignore rest.
     // The text 'OK' should be probably localized. iOS Alert does that in native.
-    var validButtons: Buttons = buttons ? buttons.slice(0, 3) : [{text: 'OK'}];
+    const validButtons: Buttons = buttons ? buttons.slice(0, 3) : [{text: 'OK'}];
-    var buttonPositive = validButtons.pop();
+    const buttonPositive = validButtons.pop();
-    var buttonNegative = validButtons.pop();
+    const buttonNegative = validButtons.pop();
-    var buttonNeutral = validButtons.pop();
+    const buttonNeutral = validButtons.pop();
     if (buttonNeutral) {
       config = {...config, buttonNeutral: buttonNeutral.text || '' };
     }

Libraries/Alert/AlertIOS.js

@@ -9,7 +9,7 @@
  */
 'use strict';
 
-var RCTAlertManager = require('NativeModules').AlertManager;
+const RCTAlertManager = require('NativeModules').AlertManager;
 
 /**
  * An Alert button type
@@ -118,7 +118,7 @@ class AlertIOS {
         'signature. The current signature is AlertIOS.prompt(title, message, callbackOrButtons, type, defaultValue, ' +
         'keyboardType) and the old syntax will be removed in a future version.');
 
-      var callback = type;
+      const callback = type;
       RCTAlertManager.alertWithArgs({
         title: title || '',
         type: 'plain-text',
@@ -129,10 +129,10 @@ class AlertIOS {
       return;
     }
 
-    var callbacks = [];
+    let callbacks = [];
-    var buttons = [];
+    const buttons = [];
-    var cancelButtonKey;
+    let cancelButtonKey;
-    var destructiveButtonKey;
+    let destructiveButtonKey;
     if (typeof callbackOrButtons === 'function') {
       callbacks = [callbackOrButtons];
     }
@@ -145,7 +145,7 @@ class AlertIOS {
           destructiveButtonKey = String(index);
         }
         if (btn.text || index < (callbackOrButtons || []).length - 1) {
-          var btnDef = {};
+          const btnDef = {};
           btnDef[index] = btn.text || '';
           buttons.push(btnDef);
         }
@@ -162,7 +162,7 @@ class AlertIOS {
       destructiveButtonKey,
       keyboardType,
     }, (id, value) => {
-      var cb = callbacks[id];
+      const cb = callbacks[id];
       cb && cb(value);
     });
   }

Libraries/Alert/RCTAlertManager.android.js

@@ -7,7 +7,7 @@
 */
 'use strict';
 
-var NativeModules = require('NativeModules');
+const NativeModules = require('NativeModules');
 
 function emptyCallback() {}
 

Libraries/Alert/RCTAlertManager.ios.js

@@ -8,6 +8,6 @@
  */
 'use strict';
 
-var RCTAlertManager = require('NativeModules').AlertManager;
+const RCTAlertManager = require('NativeModules').AlertManager;
 
 module.exports = RCTAlertManager;

Libraries/Animated/src/AnimatedWeb.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var AnimatedImplementation = require('AnimatedImplementation');
+const AnimatedImplementation = require('AnimatedImplementation');
 
 module.exports = {
   ...AnimatedImplementation,

Libraries/Animated/src/NativeAnimatedHelper.js

@@ -208,7 +208,7 @@ function validateTransform(configs: Array<Object>): void {
 }
 
 function validateStyles(styles: Object): void {
-  for (var key in styles) {
+  for (const key in styles) {
     if (!STYLES_WHITELIST.hasOwnProperty(key)) {
       throw new Error(
         `Style property '${key}' is not supported by native animated module`,
@@ -218,7 +218,7 @@ function validateStyles(styles: Object): void {
 }
 
 function validateInterpolation(config: Object): void {
-  for (var key in config) {
+  for (const key in config) {
     if (!SUPPORTED_INTERPOLATION_PARAMS.hasOwnProperty(key)) {
       throw new Error(
         `Interpolation property '${key}' is not supported by native animated module`,

Libraries/Animated/src/SpringConfig.js

@@ -77,11 +77,11 @@ function fromBouncinessAndSpeed(
     }
   }
 
-  var b = normalize(bounciness / 1.7, 0, 20);
+  let b = normalize(bounciness / 1.7, 0, 20);
   b = projectNormal(b, 0, 0.8);
-  var s = normalize(speed / 1.7, 0, 20);
+  const s = normalize(speed / 1.7, 0, 20);
-  var bouncyTension = projectNormal(s, 0.5, 200);
+  const bouncyTension = projectNormal(s, 0.5, 200);
-  var bouncyFriction = quadraticOutInterpolation(
+  const bouncyFriction = quadraticOutInterpolation(
     b,
     b3Nobounce(bouncyTension),
     0.01

Libraries/Animated/src/__tests__/Animated-test.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var Animated = require('Animated');
+let Animated = require('Animated');
 describe('Animated tests', () => {
   beforeEach(() => {
     jest.resetModules();
@@ -17,11 +17,11 @@ describe('Animated tests', () => {
   describe('Animated', () => {
 
     it('works end to end', () => {
-      var anim = new Animated.Value(0);
+      const anim = new Animated.Value(0);
 
-      var callback = jest.fn();
+      const callback = jest.fn();
 
-      var node = new Animated.__PropsOnlyForTests({
+      const node = new Animated.__PropsOnlyForTests({
         style: {
           backgroundColor: 'red',
           opacity: anim,
@@ -83,10 +83,10 @@ describe('Animated tests', () => {
     });
 
     it('does not detach on updates', () => {
-      var anim = new Animated.Value(0);
+      const anim = new Animated.Value(0);
       anim.__detach = jest.fn();
 
-      var c = new Animated.View();
+      const c = new Animated.View();
       c.props = {
         style: {
           opacity: anim,
@@ -109,10 +109,10 @@ describe('Animated tests', () => {
 
 
     it('stops animation when detached', () => {
-      var anim = new Animated.Value(0);
+      const anim = new Animated.Value(0);
-      var callback = jest.fn();
+      const callback = jest.fn();
 
-      var c = new Animated.View();
+      const c = new Animated.View();
       c.props = {
         style: {
           opacity: anim,
@@ -129,31 +129,31 @@ describe('Animated tests', () => {
     });
 
     it('triggers callback when spring is at rest', () => {
-      var anim = new Animated.Value(0);
+      const anim = new Animated.Value(0);
-      var callback = jest.fn();
+      const callback = jest.fn();
       Animated.spring(anim, {toValue: 0, velocity: 0}).start(callback);
       expect(callback).toBeCalled();
     });
 
     it('send toValue when an underdamped spring stops', () => {
-      var anim = new Animated.Value(0);
+      const anim = new Animated.Value(0);
-      var listener = jest.fn();
+      const listener = jest.fn();
       anim.addListener(listener);
       Animated.spring(anim, {toValue: 15}).start();
       jest.runAllTimers();
-      var lastValue = listener.mock.calls[listener.mock.calls.length - 2][0].value;
+      const lastValue = listener.mock.calls[listener.mock.calls.length - 2][0].value;
       expect(lastValue).not.toBe(15);
       expect(lastValue).toBeCloseTo(15);
       expect(anim.__getValue()).toBe(15);
     });
 
     it('send toValue when a critically damped spring stops', () => {
-      var anim = new Animated.Value(0);
+      const anim = new Animated.Value(0);
-      var listener = jest.fn();
+      const listener = jest.fn();
       anim.addListener(listener);
       Animated.spring(anim, {stiffness: 8000, damping: 2000, toValue: 15}).start();
       jest.runAllTimers();
-      var lastValue = listener.mock.calls[listener.mock.calls.length - 2][0].value;
+      const lastValue = listener.mock.calls[listener.mock.calls.length - 2][0].value;
       expect(lastValue).not.toBe(15);
       expect(lastValue).toBeCloseTo(15);
       expect(anim.__getValue()).toBe(15);
@@ -168,17 +168,17 @@ describe('Animated tests', () => {
   describe('Animated Sequence', () => {
 
     it('works with an empty sequence', () => {
-      var cb = jest.fn();
+      const cb = jest.fn();
       Animated.sequence([]).start(cb);
       expect(cb).toBeCalledWith({finished: true});
     });
 
     it('sequences well', () => {
-      var anim1 = {start: jest.fn()};
+      const anim1 = {start: jest.fn()};
-      var anim2 = {start: jest.fn()};
+      const anim2 = {start: jest.fn()};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var seq = Animated.sequence([anim1, anim2]);
+      const seq = Animated.sequence([anim1, anim2]);
 
       expect(anim1.start).not.toBeCalled();
       expect(anim2.start).not.toBeCalled();
@@ -199,9 +199,9 @@ describe('Animated tests', () => {
     });
 
     it('supports interrupting sequence', () => {
-      var anim1 = {start: jest.fn()};
+      const anim1 = {start: jest.fn()};
-      var anim2 = {start: jest.fn()};
+      const anim2 = {start: jest.fn()};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
       Animated.sequence([anim1, anim2]).start(cb);
 
@@ -213,11 +213,11 @@ describe('Animated tests', () => {
     });
 
     it('supports stopping sequence', () => {
-      var anim1 = {start: jest.fn(), stop: jest.fn()};
+      const anim1 = {start: jest.fn(), stop: jest.fn()};
-      var anim2 = {start: jest.fn(), stop: jest.fn()};
+      const anim2 = {start: jest.fn(), stop: jest.fn()};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var seq = Animated.sequence([anim1, anim2]);
+      const seq = Animated.sequence([anim1, anim2]);
       seq.start(cb);
       seq.stop();
 
@@ -234,10 +234,10 @@ describe('Animated tests', () => {
   describe('Animated Loop', () => {
 
     it('loops indefinitely if config not specified', () => {
-      var animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
+      const animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var loop = Animated.loop(animation);
+      const loop = Animated.loop(animation);
 
       expect(animation.start).not.toBeCalled();
 
@@ -261,10 +261,10 @@ describe('Animated tests', () => {
     });
 
     it('loops indefinitely if iterations is -1', () => {
-      var animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
+      const animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var loop = Animated.loop(animation, { iterations: -1 });
+      const loop = Animated.loop(animation, { iterations: -1 });
 
       expect(animation.start).not.toBeCalled();
 
@@ -288,10 +288,10 @@ describe('Animated tests', () => {
     });
 
     it('loops indefinitely if iterations not specified', () => {
-      var animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
+      const animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var loop = Animated.loop(animation, { anotherKey: 'value' });
+      const loop = Animated.loop(animation, { anotherKey: 'value' });
 
       expect(animation.start).not.toBeCalled();
 
@@ -315,10 +315,10 @@ describe('Animated tests', () => {
     });
 
     it('loops three times if iterations is 3', () => {
-      var animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
+      const animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var loop = Animated.loop(animation, { iterations: 3 });
+      const loop = Animated.loop(animation, { iterations: 3 });
 
       expect(animation.start).not.toBeCalled();
 
@@ -342,10 +342,10 @@ describe('Animated tests', () => {
     });
 
     it('does not loop if iterations is 1', () => {
-      var animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
+      const animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var loop = Animated.loop(animation, { iterations: 1 });
+      const loop = Animated.loop(animation, { iterations: 1 });
 
       expect(animation.start).not.toBeCalled();
 
@@ -359,10 +359,10 @@ describe('Animated tests', () => {
     });
 
     it('does not animate if iterations is 0', () => {
-      var animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
+      const animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var loop = Animated.loop(animation, { iterations: 0 });
+      const loop = Animated.loop(animation, { iterations: 0 });
 
       expect(animation.start).not.toBeCalled();
 
@@ -373,8 +373,8 @@ describe('Animated tests', () => {
     });
 
     it('supports interrupting an indefinite loop', () => {
-      var animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
+      const animation = {start: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
       Animated.loop(animation).start(cb);
       expect(animation.start).toBeCalled();
@@ -391,10 +391,10 @@ describe('Animated tests', () => {
     });
 
     it('supports stopping loop', () => {
-      var animation = {start: jest.fn(), stop: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
+      const animation = {start: jest.fn(), stop: jest.fn(), reset: jest.fn(), _isUsingNativeDriver: () => false};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var loop = Animated.loop(animation);
+      const loop = Animated.loop(animation);
       loop.start(cb);
       loop.stop();
 
@@ -411,14 +411,14 @@ describe('Animated tests', () => {
   describe('Animated Parallel', () => {
 
     it('works with an empty parallel', () => {
-      var cb = jest.fn();
+      const cb = jest.fn();
       Animated.parallel([]).start(cb);
       expect(cb).toBeCalledWith({finished: true});
     });
 
     it('works with an empty element in array', () => {
-      var anim1 = {start: jest.fn()};
+      const anim1 = {start: jest.fn()};
-      var cb = jest.fn();
+      const cb = jest.fn();
       Animated.parallel([null, anim1]).start(cb);
 
       expect(anim1.start).toBeCalled();
@@ -428,11 +428,11 @@ describe('Animated tests', () => {
     });
 
     it('parellelizes well', () => {
-      var anim1 = {start: jest.fn()};
+      const anim1 = {start: jest.fn()};
-      var anim2 = {start: jest.fn()};
+      const anim2 = {start: jest.fn()};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var par = Animated.parallel([anim1, anim2]);
+      const par = Animated.parallel([anim1, anim2]);
 
       expect(anim1.start).not.toBeCalled();
       expect(anim2.start).not.toBeCalled();
@@ -451,11 +451,11 @@ describe('Animated tests', () => {
     });
 
     it('supports stopping parallel', () => {
-      var anim1 = {start: jest.fn(), stop: jest.fn()};
+      const anim1 = {start: jest.fn(), stop: jest.fn()};
-      var anim2 = {start: jest.fn(), stop: jest.fn()};
+      const anim2 = {start: jest.fn(), stop: jest.fn()};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var seq = Animated.parallel([anim1, anim2]);
+      const seq = Animated.parallel([anim1, anim2]);
       seq.start(cb);
       seq.stop();
 
@@ -472,12 +472,12 @@ describe('Animated tests', () => {
 
 
     it('does not call stop more than once when stopping', () => {
-      var anim1 = {start: jest.fn(), stop: jest.fn()};
+      const anim1 = {start: jest.fn(), stop: jest.fn()};
-      var anim2 = {start: jest.fn(), stop: jest.fn()};
+      const anim2 = {start: jest.fn(), stop: jest.fn()};
-      var anim3 = {start: jest.fn(), stop: jest.fn()};
+      const anim3 = {start: jest.fn(), stop: jest.fn()};
-      var cb = jest.fn();
+      const cb = jest.fn();
 
-      var seq = Animated.parallel([anim1, anim2, anim3]);
+      const seq = Animated.parallel([anim1, anim2, anim3]);
       seq.start(cb);
 
       anim1.start.mock.calls[0][0]({finished: false});
@@ -502,8 +502,8 @@ describe('Animated tests', () => {
 
   describe('Animated delays', () => {
     it('should call anim after delay in sequence', () => {
-      var anim = {start: jest.fn(), stop: jest.fn()};
+      const anim = {start: jest.fn(), stop: jest.fn()};
-      var cb = jest.fn();
+      const cb = jest.fn();
       Animated.sequence([
         Animated.delay(1000),
         anim,
@@ -515,7 +515,7 @@ describe('Animated tests', () => {
       expect(cb).toBeCalledWith({finished: true});
     });
     it('should run stagger to end', () => {
-      var cb = jest.fn();
+      const cb = jest.fn();
       Animated.stagger(1000, [
         Animated.delay(1000),
         Animated.delay(1000),
@@ -528,17 +528,17 @@ describe('Animated tests', () => {
 
   describe('Animated Events', () => {
     it('should map events', () => {
-      var value = new Animated.Value(0);
+      const value = new Animated.Value(0);
-      var handler = Animated.event(
+      const handler = Animated.event(
         [null, {state: {foo: value}}],
       );
       handler({bar: 'ignoreBar'}, {state: {baz: 'ignoreBaz', foo: 42}});
       expect(value.__getValue()).toBe(42);
     });
     it('should call listeners', () => {
-      var value = new Animated.Value(0);
+      const value = new Animated.Value(0);
-      var listener = jest.fn();
+      const listener = jest.fn();
-      var handler = Animated.event(
+      const handler = Animated.event(
         [{foo: value}],
         {listener},
       );
@@ -548,14 +548,14 @@ describe('Animated tests', () => {
       expect(listener).toBeCalledWith({foo: 42});
     });
     it('should call forked event listeners', () => {
-      var value = new Animated.Value(0);
+      const value = new Animated.Value(0);
-      var listener = jest.fn();
+      const listener = jest.fn();
-      var handler = Animated.event(
+      const handler = Animated.event(
         [{foo: value}],
         {listener},
       );
-      var listener2 = jest.fn();
+      const listener2 = jest.fn();
-      var forkedHandler = Animated.forkEvent(handler, listener2);
+      const forkedHandler = Animated.forkEvent(handler, listener2);
       forkedHandler({foo: 42});
       expect(value.__getValue()).toBe(42);
       expect(listener.mock.calls.length).toBe(1);
@@ -567,9 +567,9 @@ describe('Animated tests', () => {
 
   describe('Animated Interactions', () => {
     /*eslint-disable no-shadow*/
-    var Animated;
+    let Animated;
     /*eslint-enable*/
-    var InteractionManager;
+    let InteractionManager;
 
     beforeEach(() => {
       jest.mock('InteractionManager');
@@ -584,8 +584,8 @@ describe('Animated tests', () => {
     it('registers an interaction by default', () => {
       InteractionManager.createInteractionHandle.mockReturnValue(777);
 
-      var value = new Animated.Value(0);
+      const value = new Animated.Value(0);
-      var callback = jest.fn();
+      const callback = jest.fn();
       Animated.timing(value, {
         toValue: 100,
         duration: 100,
@@ -598,8 +598,8 @@ describe('Animated tests', () => {
     });
 
     it('does not register an interaction when specified', () => {
-      var value = new Animated.Value(0);
+      const value = new Animated.Value(0);
-      var callback = jest.fn();
+      const callback = jest.fn();
       Animated.timing(value, {
         toValue: 100,
         duration: 100,
@@ -615,8 +615,8 @@ describe('Animated tests', () => {
 
   describe('Animated Tracking', () => {
     it('should track values', () => {
-      var value1 = new Animated.Value(0);
+      const value1 = new Animated.Value(0);
-      var value2 = new Animated.Value(0);
+      const value2 = new Animated.Value(0);
       Animated.timing(value2, {
         toValue: value1,
         duration: 0,
@@ -628,8 +628,8 @@ describe('Animated tests', () => {
     });
 
     it('should track interpolated values', () => {
-      var value1 = new Animated.Value(0);
+      const value1 = new Animated.Value(0);
-      var value2 = new Animated.Value(0);
+      const value2 = new Animated.Value(0);
       Animated.timing(value2, {
         toValue: value1.interpolate({
           inputRange: [0, 2],
@@ -642,8 +642,8 @@ describe('Animated tests', () => {
     });
 
     it('should stop tracking when animated', () => {
-      var value1 = new Animated.Value(0);
+      const value1 = new Animated.Value(0);
-      var value2 = new Animated.Value(0);
+      const value2 = new Animated.Value(0);
       Animated.timing(value2, {
         toValue: value1,
         duration: 0,
@@ -661,11 +661,11 @@ describe('Animated tests', () => {
 
   describe('Animated Vectors', () => {
     it('should animate vectors', () => {
-      var vec = new Animated.ValueXY();
+      const vec = new Animated.ValueXY();
 
-      var callback = jest.fn();
+      const callback = jest.fn();
 
-      var node = new Animated.__PropsOnlyForTests({
+      const node = new Animated.__PropsOnlyForTests({
         style: {
           opacity: vec.x.interpolate({
             inputRange: [0, 42],
@@ -711,8 +711,8 @@ describe('Animated tests', () => {
     });
 
     it('should track vectors', () => {
-      var value1 = new Animated.ValueXY();
+      const value1 = new Animated.ValueXY();
-      var value2 = new Animated.ValueXY();
+      const value2 = new Animated.ValueXY();
       Animated.timing(value2, {
         toValue: value1,
         duration: 0,
@@ -727,8 +727,8 @@ describe('Animated tests', () => {
     });
 
     it('should track with springs', () => {
-      var value1 = new Animated.ValueXY();
+      const value1 = new Animated.ValueXY();
-      var value2 = new Animated.ValueXY();
+      const value2 = new Animated.ValueXY();
       Animated.spring(value2, {
         toValue: value1,
         tension: 3000, // faster spring for faster test
@@ -747,9 +747,9 @@ describe('Animated tests', () => {
 
   describe('Animated Listeners', () => {
     it('should get updates', () => {
-      var value1 = new Animated.Value(0);
+      const value1 = new Animated.Value(0);
-      var listener = jest.fn();
+      const listener = jest.fn();
-      var id = value1.addListener(listener);
+      const id = value1.addListener(listener);
       value1.setValue(42);
       expect(listener.mock.calls.length).toBe(1);
       expect(listener).toBeCalledWith({value: 42});
@@ -765,8 +765,8 @@ describe('Animated tests', () => {
     });
 
     it('should removeAll', () => {
-      var value1 = new Animated.Value(0);
+      const value1 = new Animated.Value(0);
-      var listener = jest.fn();
+      const listener = jest.fn();
       [1,2,3,4].forEach(() => value1.addListener(listener));
       value1.setValue(42);
       expect(listener.mock.calls.length).toBe(4);

Libraries/Animated/src/__tests__/Easing-test.js

@@ -8,10 +8,10 @@
  */
 'use strict';
 
-var Easing = require('Easing');
+const Easing = require('Easing');
 describe('Easing', () => {
   it('should work with linear', () => {
-    var easing = Easing.linear;
+    const easing = Easing.linear;
 
     expect(easing(0)).toBe(0);
     expect(easing(0.5)).toBe(0.5);
@@ -20,7 +20,7 @@ describe('Easing', () => {
   });
 
   it('should work with ease in linear', () => {
-    var easing = Easing.in(Easing.linear);
+    const easing = Easing.in(Easing.linear);
     expect(easing(0)).toBe(0);
     expect(easing(0.5)).toBe(0.5);
     expect(easing(0.8)).toBe(0.8);
@@ -28,7 +28,7 @@ describe('Easing', () => {
   });
 
   it('should work with easy out linear', () => {
-    var easing = Easing.out(Easing.linear);
+    const easing = Easing.out(Easing.linear);
     expect(easing(0)).toBe(0);
     expect(easing(0.5)).toBe(0.5);
     expect(easing(0.6)).toBe(0.6);
@@ -39,8 +39,8 @@ describe('Easing', () => {
     function easeInQuad(t) {
       return t * t;
     }
-    var easing = Easing.in(Easing.quad);
+    const easing = Easing.in(Easing.quad);
-    for (var t = -0.5; t < 1.5; t += 0.1) {
+    for (let t = -0.5; t < 1.5; t += 0.1) {
       expect(easing(t)).toBe(easeInQuad(t));
     }
   });
@@ -49,8 +49,8 @@ describe('Easing', () => {
     function easeOutQuad(t) {
       return -t * (t - 2);
     }
-    var easing = Easing.out(Easing.quad);
+    const easing = Easing.out(Easing.quad);
-    for (var t = 0; t <= 1; t += 0.1) {
+    for (let t = 0; t <= 1; t += 0.1) {
       expect(easing(1)).toBe(easeOutQuad(1));
     }
   });
@@ -63,31 +63,31 @@ describe('Easing', () => {
       }
       return -((t - 1) * (t - 3) - 1) / 2;
     }
-    var easing = Easing.inOut(Easing.quad);
+    const easing = Easing.inOut(Easing.quad);
-    for (var t = -0.5; t < 1.5; t += 0.1) {
+    for (let t = -0.5; t < 1.5; t += 0.1) {
       expect(easing(t)).toBeCloseTo(easeInOutQuad(t), 4);
     }
   });
 
   it('should satisfy boundary conditions with elastic', () => {
-    for (var b = 0; b < 4; b += 0.3) {
+    for (let b = 0; b < 4; b += 0.3) {
-      var easing = Easing.elastic(b);
+      const easing = Easing.elastic(b);
       expect(easing(0)).toBe(0);
       expect(easing(1)).toBe(1);
     }
   });
 
   function sampleEasingFunction(easing) {
-    var DURATION = 300;
+    const DURATION = 300;
-    var tickCount = Math.round(DURATION * 60 / 1000);
+    const tickCount = Math.round(DURATION * 60 / 1000);
-    var samples = [];
+    const samples = [];
-    for (var i = 0; i <= tickCount; i++) {
+    for (let i = 0; i <= tickCount; i++) {
       samples.push(easing(i / tickCount));
     }
     return samples;
   }
 
-  var Samples = {
+  const Samples = {
     in_quad: [0,0.0030864197530864196,0.012345679012345678,0.027777777777777776,0.04938271604938271,0.0771604938271605,0.1111111111111111,0.15123456790123457,0.19753086419753085,0.25,0.308641975308642,0.37345679012345684,0.4444444444444444,0.5216049382716049,0.6049382716049383,0.6944444444444445,0.7901234567901234,0.8919753086419753,1],
     out_quad: [0,0.10802469135802469,0.20987654320987653,0.3055555555555555,0.3950617283950617,0.47839506172839513,0.5555555555555556,0.6265432098765432,0.691358024691358,0.75,0.8024691358024691,0.8487654320987654,0.888888888888889,0.9228395061728394,0.9506172839506174,0.9722222222222221,0.9876543209876543,0.9969135802469136,1],
     inOut_quad: [0,0.006172839506172839,0.024691358024691357,0.05555555555555555,0.09876543209876543,0.154320987654321,0.2222222222222222,0.30246913580246915,0.3950617283950617,0.5,0.6049382716049383,0.697530864197531,0.7777777777777777,0.845679012345679,0.9012345679012346,0.9444444444444444,0.9753086419753086,0.9938271604938271,1],
@@ -109,13 +109,13 @@ describe('Easing', () => {
 
   Object.keys(Samples).forEach(function(type) {
     it('should ease ' + type, function() {
-      var [modeName, easingName, isFunction] = type.split('_');
+      const [modeName, easingName, isFunction] = type.split('_');
-      var easing = Easing[easingName];
+      let easing = Easing[easingName];
       if (isFunction !== undefined) {
         easing = easing();
       }
-      var computed = sampleEasingFunction(Easing[modeName](easing));
+      const computed = sampleEasingFunction(Easing[modeName](easing));
-      var samples = Samples[type];
+      const samples = Samples[type];
 
       computed.forEach((value, key) => {
         expect(value).toBeCloseTo(samples[key], 2);

Libraries/Animated/src/__tests__/Interpolation-test.js

@@ -8,12 +8,12 @@
  */
 'use strict';
 
-var AnimatedInterpolation = require('../nodes/AnimatedInterpolation');
+const AnimatedInterpolation = require('../nodes/AnimatedInterpolation');
-var Easing = require('Easing');
+const Easing = require('Easing');
 
 describe('Interpolation', () => {
   it('should work with defaults', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: [0, 1],
     });
@@ -25,7 +25,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with output range', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: [100, 200],
     });
@@ -37,7 +37,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with input range', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [100, 200],
       outputRange: [0, 1],
     });
@@ -65,7 +65,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with empty input range', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 10, 10],
       outputRange: [1, 2, 3],
       extrapolate: 'extend',
@@ -79,7 +79,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with empty output range', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [1, 2, 3],
       outputRange: [0, 10, 10],
       extrapolate: 'extend',
@@ -94,7 +94,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with easing', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: [0, 1],
       easing: Easing.quad,
@@ -107,7 +107,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with extrapolate', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    let interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: [0, 1],
       extrapolate: 'extend',
@@ -139,7 +139,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with keyframes with extrapolate', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 10, 100, 1000],
       outputRange: [0, 5, 50, 500],
       extrapolate: true,
@@ -157,7 +157,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with keyframes without extrapolate', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1, 2],
       outputRange: [0.2, 1, 0.2],
       extrapolate: 'clamp',
@@ -183,7 +183,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with negative infinite', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [-Infinity, 0],
       outputRange: [-Infinity, 0],
       easing: Easing.quad,
@@ -199,7 +199,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with positive infinite', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [5, Infinity],
       outputRange: [5, Infinity],
       easing: Easing.quad,
@@ -217,7 +217,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with output ranges as string', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: ['rgba(0, 100, 200, 0)', 'rgba(50, 150, 250, 0.4)'],
     });
@@ -228,7 +228,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with output ranges as short hex string', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: ['#024', '#9BF'],
     });
@@ -239,7 +239,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with output ranges as long hex string', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: ['#FF9500', '#87FC70'],
     });
@@ -250,7 +250,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with output ranges with mixed hex and rgba strings', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: ['rgba(100, 120, 140, .4)', '#87FC70'],
     });
@@ -261,7 +261,7 @@ describe('Interpolation', () => {
   });
 
   it('should work with negative and decimal values in string ranges', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: ['-100.5deg', '100deg'],
     });
@@ -272,7 +272,7 @@ describe('Interpolation', () => {
   });
 
   it('should crash when chaining an interpolation that returns a string', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: [0, 1],
     });
@@ -282,7 +282,7 @@ describe('Interpolation', () => {
   });
 
   it('should support a mix of color patterns', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1, 2],
       outputRange: ['rgba(0, 100, 200, 0)', 'rgb(50, 150, 250)', 'red'],
     });
@@ -303,7 +303,7 @@ describe('Interpolation', () => {
   });
 
   it('should round the alpha channel of a color to the nearest thousandth', () => {
-    var interpolation = AnimatedInterpolation.__createInterpolation({
+    const interpolation = AnimatedInterpolation.__createInterpolation({
       inputRange: [0, 1],
       outputRange: ['rgba(0, 0, 0, 0)', 'rgba(0, 0, 0, 1)'],
     });

Libraries/Animated/src/__tests__/bezier-test.js

@@ -10,9 +10,9 @@
 
 'use strict';
 
-var bezier = require('bezier');
+const bezier = require('bezier');
 
-var identity = function(x) {
+const identity = function(x) {
   return x;
 };
 
@@ -30,15 +30,15 @@ function allEquals(be1, be2, samples, assertion) {
   if (!assertion) {
     assertion = assertClose;
   }
-  for (var i = 0; i <= samples; ++i) {
+  for (let i = 0; i <= samples; ++i) {
-    var x = i / samples;
+    const x = i / samples;
     assertion(be1(x), be2(x));
   }
 }
 
 function repeat(n) {
   return function(f) {
-    for (var i = 0; i < n; ++i) {
+    for (let i = 0; i < n; ++i) {
       f(i);
     }
   };
@@ -74,11 +74,8 @@ describe('bezier', function() {
   describe('common properties', function() {
     it('should be the right value at extremes', function() {
       repeat(10)(function() {
-        var a = Math.random(),
+        const a = Math.random(), b = 2 * Math.random() - 0.5, c = Math.random(), d = 2 * Math.random() - 0.5;
-          b = 2 * Math.random() - 0.5,
+        const easing = bezier(a, b, c, d);
-          c = Math.random(),
-          d = 2 * Math.random() - 0.5;
-        var easing = bezier(a, b, c, d);
         expect(easing(0)).toBe(0);
         expect(easing(1)).toBe(1);
       });
@@ -86,13 +83,10 @@ describe('bezier', function() {
 
     it('should approach the projected value of its x=y projected curve', function() {
       repeat(10)(function() {
-        var a = Math.random(),
+        const a = Math.random(), b = Math.random(), c = Math.random(), d = Math.random();
-          b = Math.random(),
+        const easing = bezier(a, b, c, d);
-          c = Math.random(),
+        const projected = bezier(b, a, d, c);
-          d = Math.random();
+        const composed = function(x) {
-        var easing = bezier(a, b, c, d);
-        var projected = bezier(b, a, d, c);
-        var composed = function(x) {
           return projected(easing(x));
         };
         allEquals(identity, composed, 100, makeAssertCloseWithPrecision(2));
@@ -102,10 +96,7 @@ describe('bezier', function() {
   describe('two same instances', function() {
     it('should be strictly equals', function() {
       repeat(10)(function() {
-        var a = Math.random(),
+        const a = Math.random(), b = 2 * Math.random() - 0.5, c = Math.random(), d = 2 * Math.random() - 0.5;
-          b = 2 * Math.random() - 0.5,
-          c = Math.random(),
-          d = 2 * Math.random() - 0.5;
         allEquals(bezier(a, b, c, d), bezier(a, b, c, d), 100, 0);
       });
     });
@@ -113,22 +104,16 @@ describe('bezier', function() {
   describe('symetric curves', function() {
     it('should have a central value y~=0.5 at x=0.5', function() {
       repeat(10)(function() {
-        var a = Math.random(),
+        const a = Math.random(), b = 2 * Math.random() - 0.5, c = 1 - a, d = 1 - b;
-          b = 2 * Math.random() - 0.5,
+        const easing = bezier(a, b, c, d);
-          c = 1 - a,
-          d = 1 - b;
-        var easing = bezier(a, b, c, d);
         assertClose(easing(0.5), 0.5, 2);
       });
     });
     it('should be symmetrical', function() {
       repeat(10)(function() {
-        var a = Math.random(),
+        const a = Math.random(), b = 2 * Math.random() - 0.5, c = 1 - a, d = 1 - b;
-          b = 2 * Math.random() - 0.5,
+        const easing = bezier(a, b, c, d);
-          c = 1 - a,
+        const sym = function(x) {
-          d = 1 - b;
-        var easing = bezier(a, b, c, d);
-        var sym = function(x) {
           return 1 - easing(1 - x);
         };
         allEquals(easing, sym, 100, makeAssertCloseWithPrecision(2));

Libraries/Animated/src/bezier.js

@@ -8,15 +8,15 @@
 'use strict';
 
  // These values are established by empiricism with tests (tradeoff: performance VS precision)
- var NEWTON_ITERATIONS = 4;
+ const NEWTON_ITERATIONS = 4;
- var NEWTON_MIN_SLOPE = 0.001;
+ const NEWTON_MIN_SLOPE = 0.001;
- var SUBDIVISION_PRECISION = 0.0000001;
+ const SUBDIVISION_PRECISION = 0.0000001;
- var SUBDIVISION_MAX_ITERATIONS = 10;
+ const SUBDIVISION_MAX_ITERATIONS = 10;
 
- var kSplineTableSize = 11;
+ const kSplineTableSize = 11;
- var kSampleStepSize = 1.0 / (kSplineTableSize - 1.0);
+ const kSampleStepSize = 1.0 / (kSplineTableSize - 1.0);
 
- var float32ArraySupported = typeof Float32Array === 'function';
+ const float32ArraySupported = typeof Float32Array === 'function';
 
  function A (aA1, aA2) { return 1.0 - 3.0 * aA2 + 3.0 * aA1; }
  function B (aA1, aA2) { return 3.0 * aA2 - 6.0 * aA1; }
@@ -29,7 +29,7 @@
  function getSlope (aT, aA1, aA2) { return 3.0 * A(aA1, aA2) * aT * aT + 2.0 * B(aA1, aA2) * aT + C(aA1); }
 
  function binarySubdivide (aX, aA, aB, mX1, mX2) {
-   var currentX, currentT, i = 0;
+   let currentX, currentT, i = 0;
    do {
      currentT = aA + (aB - aA) / 2.0;
      currentX = calcBezier(currentT, mX1, mX2) - aX;
@@ -43,12 +43,12 @@
  }
 
  function newtonRaphsonIterate (aX, aGuessT, mX1, mX2) {
-  for (var i = 0; i < NEWTON_ITERATIONS; ++i) {
+  for (let i = 0; i < NEWTON_ITERATIONS; ++i) {
-    var currentSlope = getSlope(aGuessT, mX1, mX2);
+    const currentSlope = getSlope(aGuessT, mX1, mX2);
     if (currentSlope === 0.0) {
       return aGuessT;
     }
-    var currentX = calcBezier(aGuessT, mX1, mX2) - aX;
+    const currentX = calcBezier(aGuessT, mX1, mX2) - aX;
     aGuessT -= currentX / currentSlope;
   }
   return aGuessT;
@@ -60,17 +60,17 @@
    }
 
    // Precompute samples table
-   var sampleValues = float32ArraySupported ? new Float32Array(kSplineTableSize) : new Array(kSplineTableSize);
+   const sampleValues = float32ArraySupported ? new Float32Array(kSplineTableSize) : new Array(kSplineTableSize);
    if (mX1 !== mY1 || mX2 !== mY2) {
-     for (var i = 0; i < kSplineTableSize; ++i) {
+     for (let i = 0; i < kSplineTableSize; ++i) {
        sampleValues[i] = calcBezier(i * kSampleStepSize, mX1, mX2);
      }
    }
 
    function getTForX (aX) {
-     var intervalStart = 0.0;
+     let intervalStart = 0.0;
-     var currentSample = 1;
+     let currentSample = 1;
-     var lastSample = kSplineTableSize - 1;
+     const lastSample = kSplineTableSize - 1;
 
      for (; currentSample !== lastSample && sampleValues[currentSample] <= aX; ++currentSample) {
        intervalStart += kSampleStepSize;
@@ -78,10 +78,10 @@
      --currentSample;
 
      // Interpolate to provide an initial guess for t
-     var dist = (aX - sampleValues[currentSample]) / (sampleValues[currentSample + 1] - sampleValues[currentSample]);
+     const dist = (aX - sampleValues[currentSample]) / (sampleValues[currentSample + 1] - sampleValues[currentSample]);
-     var guessForT = intervalStart + dist * kSampleStepSize;
+     const guessForT = intervalStart + dist * kSampleStepSize;
 
-     var initialSlope = getSlope(guessForT, mX1, mX2);
+     const initialSlope = getSlope(guessForT, mX1, mX2);
      if (initialSlope >= NEWTON_MIN_SLOPE) {
        return newtonRaphsonIterate(aX, guessForT, mX1, mX2);
      } else if (initialSlope === 0.0) {

Libraries/BatchedBridge/__mocks__/MessageQueueTestConfig.js

@@ -7,12 +7,12 @@
  * These don't actually exist anywhere in the code.
  */
 'use strict';
-var remoteModulesConfig = [
+const remoteModulesConfig = [
   ['RemoteModule1',null,['remoteMethod','promiseMethod'],[]],
   ['RemoteModule2',null,['remoteMethod','promiseMethod'],[]],
 ];
 
-var MessageQueueTestConfig = {
+const MessageQueueTestConfig = {
   remoteModuleConfig: remoteModulesConfig,
 };
 

Libraries/BatchedBridge/__mocks__/MessageQueueTestModule.js

@@ -12,7 +12,7 @@
  * correctly dispatches to commonJS modules. The `testHook` is overriden by test
  * cases.
  */
-var MessageQueueTestModule = {
+const MessageQueueTestModule = {
   testHook1: function() {
   },
   testHook2: function() {

Libraries/Blob/__tests__/Blob-test.js

@@ -13,7 +13,7 @@ jest.setMock('NativeModules', {
   BlobModule: require('../__mocks__/BlobModule'),
 });
 
-var Blob = require('Blob');
+const Blob = require('Blob');
 
 describe('Blob', function() {
   it('should create empty blob', () => {

Libraries/Blob/__tests__/BlobManager-test.js

@@ -13,8 +13,8 @@ jest.setMock('NativeModules', {
   BlobModule: require('../__mocks__/BlobModule'),
 });
 
-var Blob = require('Blob');
+const Blob = require('Blob');
-var BlobManager = require('BlobManager');
+const BlobManager = require('BlobManager');
 
 describe('BlobManager', function() {
   it('should create blob from parts', () => {

Libraries/Blob/__tests__/FileReader-test.js

@@ -14,8 +14,8 @@ jest.unmock('event-target-shim').setMock('NativeModules', {
   FileReaderModule: require('../__mocks__/FileReaderModule'),
 });
 
-var Blob = require('Blob');
+const Blob = require('Blob');
-var FileReader = require('FileReader');
+const FileReader = require('FileReader');
 
 describe('FileReader', function() {
   it('should read blob as text', async () => {

Libraries/BugReporting/getReactData.js

@@ -15,16 +15,16 @@
  * https://github.com/facebook/react-devtools/blob/master/backend/getData.js
  */
 function getData(element: Object): Object {
-  var children = null;
+  let children = null;
-  var props = null;
+  let props = null;
-  var state = null;
+  let state = null;
-  var context = null;
+  let context = null;
-  var updater = null;
+  let updater = null;
-  var name = null;
+  let name = null;
-  var type = null;
+  let type = null;
-  var text = null;
+  let text = null;
-  var publicInstance = null;
+  let publicInstance = null;
-  var nodeType = 'Native';
+  let nodeType = 'Native';
   // If the parent is a native node without rendered children, but with
   // multiple string children, then the `element` that gets passed in here is
   // a plain value -- a string or number.
@@ -80,7 +80,7 @@ function getData(element: Object): Object {
   }
 
   if (element._instance) {
-    var inst = element._instance;
+    const inst = element._instance;
     updater = {
       setState: inst.setState && inst.setState.bind(inst),
       forceUpdate: inst.forceUpdate && inst.forceUpdate.bind(inst),
@@ -113,7 +113,7 @@ function getData(element: Object): Object {
 }
 
 function setInProps(internalInst, path: Array<string | number>, value: any) {
-  var element = internalInst._currentElement;
+  const element = internalInst._currentElement;
   internalInst._currentElement = {
     ...element,
     props: copyWithSet(element.props, path, value),
@@ -132,16 +132,16 @@ function setInContext(inst, path: Array<string | number>, value: any) {
 }
 
 function setIn(obj: Object, path: Array<string | number>, value: any) {
-  var last = path.pop();
+  const last = path.pop();
-  var parent = path.reduce((obj_, attr) => obj_ ? obj_[attr] : null, obj);
+  const parent = path.reduce((obj_, attr) => obj_ ? obj_[attr] : null, obj);
   if (parent) {
     parent[last] = value;
   }
 }
 
 function childrenList(children) {
-  var res = [];
+  const res = [];
-  for (var name in children) {
+  for (const name in children) {
     res.push(children[name]);
   }
   return res;
@@ -151,8 +151,8 @@ function copyWithSetImpl(obj, path, idx, value) {
   if (idx >= path.length) {
     return value;
   }
-  var key = path[idx];
+  const key = path[idx];
-  var updated = Array.isArray(obj) ? obj.slice() : {...obj};
+  const updated = Array.isArray(obj) ? obj.slice() : {...obj};
   // $FlowFixMe number or string is fine here
   updated[key] = copyWithSetImpl(obj[key], path, idx + 1, value);
   return updated;

Libraries/CameraRoll/ImagePickerIOS.js

@@ -8,9 +8,9 @@
  */
 'use strict';
 
-var RCTImagePicker = require('NativeModules').ImagePickerIOS;
+const RCTImagePicker = require('NativeModules').ImagePickerIOS;
 
-var ImagePickerIOS = {
+const ImagePickerIOS = {
   canRecordVideos: function(callback: Function) {
     return RCTImagePicker.canRecordVideos(callback);
   },

Libraries/Color/normalizeColor.js

@@ -10,7 +10,7 @@
 'use strict';
 
 function normalizeColor(color: string | number): ?number {
-  var match;
+  let match;
 
   if (typeof color === 'number') {
     if (color >>> 0 === color && color >= 0 && color <= 0xffffffff) {
@@ -31,18 +31,18 @@ function normalizeColor(color: string | number): ?number {
   if ((match = matchers.rgb.exec(color))) {
     return (
       (// b
-      parse255(match[1]) << 24 | // r
+      (parse255(match[1]) << 24 | // r
       parse255(match[2]) << 16 | // g
-      parse255(match[3]) << 8 | 0x000000ff) // a
+      parse255(match[3]) << 8 | 0x000000ff)) // a
     ) >>> 0;
   }
 
   if ((match = matchers.rgba.exec(color))) {
     return (
       (// b
-      parse255(match[1]) << 24 | // r
+      (parse255(match[1]) << 24 | // r
       parse255(match[2]) << 16 | // g
-      parse255(match[3]) << 8 | parse1(match[4])) // a
+      parse255(match[3]) << 8 | parse1(match[4]))) // a
     ) >>> 0;
   }
 
@@ -114,11 +114,11 @@ function hue2rgb(p: number, q: number, t: number): number {
 }
 
 function hslToRgb(h: number, s: number, l: number): number {
-  var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
+  const q = l < 0.5 ? l * (1 + s) : l + s - l * s;
-  var p = 2 * l - q;
+  const p = 2 * l - q;
-  var r = hue2rgb(p, q, h + 1 / 3);
+  const r = hue2rgb(p, q, h + 1 / 3);
-  var g = hue2rgb(p, q, h);
+  const g = hue2rgb(p, q, h);
-  var b = hue2rgb(p, q, h - 1 / 3);
+  const b = hue2rgb(p, q, h - 1 / 3);
 
   return (
     Math.round(r * 255) << 24 |
@@ -128,14 +128,14 @@ function hslToRgb(h: number, s: number, l: number): number {
 }
 
 // var INTEGER = '[-+]?\\d+';
-var NUMBER = '[-+]?\\d*\\.?\\d+';
+const NUMBER = '[-+]?\\d*\\.?\\d+';
-var PERCENTAGE = NUMBER + '%';
+const PERCENTAGE = NUMBER + '%';
 
 function call(...args) {
   return '\\(\\s*(' + args.join(')\\s*,\\s*(') + ')\\s*\\)';
 }
 
-var matchers = {
+const matchers = {
   rgb: new RegExp('rgb' + call(NUMBER, NUMBER, NUMBER)),
   rgba: new RegExp('rgba' + call(NUMBER, NUMBER, NUMBER, NUMBER)),
   hsl: new RegExp('hsl' + call(NUMBER, PERCENTAGE, PERCENTAGE)),
@@ -147,7 +147,7 @@ var matchers = {
 };
 
 function parse255(str: string): number {
-  var int = parseInt(str, 10);
+  const int = parseInt(str, 10);
   if (int < 0) {
     return 0;
   }
@@ -158,12 +158,12 @@ function parse255(str: string): number {
 }
 
 function parse360(str: string): number {
-  var int = parseFloat(str);
+  const int = parseFloat(str);
   return (((int % 360) + 360) % 360) / 360;
 }
 
 function parse1(str: string): number {
-  var num = parseFloat(str);
+  const num = parseFloat(str);
   if (num < 0) {
     return 0;
   }
@@ -175,7 +175,7 @@ function parse1(str: string): number {
 
 function parsePercentage(str: string): number {
   // parseFloat conveniently ignores the final %
-  var int = parseFloat(str);
+  const int = parseFloat(str);
   if (int < 0) {
     return 0;
   }
@@ -185,7 +185,7 @@ function parsePercentage(str: string): number {
   return int / 100;
 }
 
-var names = {
+const names = {
   transparent: 0x00000000,
 
   // http://www.w3.org/TR/css3-color/#svg-color

Libraries/Core/Devtools/__tests__/parseErrorStack-test.js

@@ -9,7 +9,7 @@
 'use strict';
 
 
-var parseErrorStack = require('parseErrorStack');
+const parseErrorStack = require('parseErrorStack');
 
 function getFakeError() {
   return new Error('Happy Cat');
@@ -18,24 +18,24 @@ function getFakeError() {
 describe('parseErrorStack', function() {
 
   it('parses error stack', function() {
-    var stack = parseErrorStack(getFakeError());
+    const stack = parseErrorStack(getFakeError());
     expect(stack.length).toBeGreaterThan(0);
 
-    var firstFrame = stack[0];
+    const firstFrame = stack[0];
     expect(firstFrame.methodName).toEqual('getFakeError');
     expect(firstFrame.file).toMatch(/parseErrorStack-test\.js$/);
   });
 
   it('supports framesToPop', function() {
     function getWrappedError() {
-      var error = getFakeError();
+      const error = getFakeError();
       error.framesToPop = 1;
       return error;
     }
 
     // Make sure framesToPop == 1 causes it to ignore getFakeError
     // stack frame
-    var stack = parseErrorStack(getWrappedError());
+    const stack = parseErrorStack(getWrappedError());
     expect(stack[0].methodName).toEqual('getWrappedError');
   });
 

Libraries/Core/__mocks__/ErrorUtils.js

@@ -19,7 +19,7 @@ function reportError(error) {
   throw error;
 }
 
-var ErrorUtils = {
+const ErrorUtils = {
   apply: jest.fn(execute),
   applyWithGuard: jest.fn(execute),
   guard: jest.fn(callback => callback),

Libraries/Experimental/IncrementalExample.js

@@ -153,7 +153,7 @@ function burnCPU(milliseconds) {
   while (performanceNow() < (start + milliseconds)) {}
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   scrollView: {
     margin: 10,
     backgroundColor: 'white',

Libraries/Geolocation/Geolocation.js

@@ -23,8 +23,8 @@ const LocationEventEmitter = new NativeEventEmitter(RCTLocationObserver);
 const Platform = require('Platform');
 const PermissionsAndroid = require('PermissionsAndroid');
 
-var subscriptions = [];
+let subscriptions = [];
-var updatesEnabled = false;
+let updatesEnabled = false;
 
 type GeoConfiguration = {
   skipPermissionRequests: bool;
@@ -44,7 +44,7 @@ type GeoOptions = {
  *
  * See https://facebook.github.io/react-native/docs/geolocation.html
  */
-var Geolocation = {
+const Geolocation = {
 
   /*
     * Sets configuration options that will be used in all location requests.
@@ -116,7 +116,7 @@ var Geolocation = {
       RCTLocationObserver.startObserving(options || {});
       updatesEnabled = true;
     }
-    var watchID = subscriptions.length;
+    const watchID = subscriptions.length;
     subscriptions.push([
       LocationEventEmitter.addListener(
         'geolocationDidChange',
@@ -131,7 +131,7 @@ var Geolocation = {
   },
 
   clearWatch: function(watchID: number) {
-    var sub = subscriptions[watchID];
+    const sub = subscriptions[watchID];
     if (!sub) {
       // Silently exit when the watchID is invalid or already cleared
       // This is consistent with timers
@@ -140,10 +140,10 @@ var Geolocation = {
 
     sub[0].remove();
     // array element refinements not yet enabled in Flow
-    var sub1 = sub[1]; sub1 && sub1.remove();
+    const sub1 = sub[1]; sub1 && sub1.remove();
     subscriptions[watchID] = undefined;
-    var noWatchers = true;
+    let noWatchers = true;
-    for (var ii = 0; ii < subscriptions.length; ii++) {
+    for (let ii = 0; ii < subscriptions.length; ii++) {
       if (subscriptions[ii]) {
         noWatchers = false; // still valid subscriptions
       }
@@ -157,13 +157,13 @@ var Geolocation = {
     if (updatesEnabled) {
       RCTLocationObserver.stopObserving();
       updatesEnabled = false;
-      for (var ii = 0; ii < subscriptions.length; ii++) {
+      for (let ii = 0; ii < subscriptions.length; ii++) {
-        var sub = subscriptions[ii];
+        const sub = subscriptions[ii];
         if (sub) {
           warning(false, 'Called stopObserving with existing subscriptions.');
           sub[0].remove();
           // array element refinements not yet enabled in Flow
-          var sub1 = sub[1]; sub1 && sub1.remove();
+          const sub1 = sub[1]; sub1 && sub1.remove();
         }
       }
       subscriptions = [];

Libraries/Image/AssetRegistry.js

@@ -21,7 +21,7 @@ export type PackagerAsset = {
   +type: string,
 };
 
-var assets: Array<PackagerAsset> = [];
+const assets: Array<PackagerAsset> = [];
 
 function registerAsset(asset: PackagerAsset): number {
   // `push` returns new array length, so the first asset will

Libraries/Image/AssetSourceResolver.js

@@ -29,9 +29,9 @@ const invariant = require('fbjs/lib/invariant');
  * Returns a path like 'assets/AwesomeModule/icon@2x.png'
  */
 function getScaledAssetPath(asset): string {
-  var scale = AssetSourceResolver.pickScale(asset.scales, PixelRatio.get());
+  const scale = AssetSourceResolver.pickScale(asset.scales, PixelRatio.get());
-  var scaleSuffix = scale === 1 ? '' : '@' + scale + 'x';
+  const scaleSuffix = scale === 1 ? '' : '@' + scale + 'x';
-  var assetDir = assetPathUtils.getBasePath(asset);
+  const assetDir = assetPathUtils.getBasePath(asset);
   return assetDir + '/' + asset.name + scaleSuffix + '.' + asset.type;
 }
 
@@ -39,9 +39,9 @@ function getScaledAssetPath(asset): string {
  * Returns a path like 'drawable-mdpi/icon.png'
  */
 function getAssetPathInDrawableFolder(asset): string {
-  var scale = AssetSourceResolver.pickScale(asset.scales, PixelRatio.get());
+  const scale = AssetSourceResolver.pickScale(asset.scales, PixelRatio.get());
-  var drawbleFolder = assetPathUtils.getAndroidResourceFolderName(asset, scale);
+  const drawbleFolder = assetPathUtils.getAndroidResourceFolderName(asset, scale);
-  var fileName = assetPathUtils.getAndroidResourceIdentifier(asset);
+  const fileName = assetPathUtils.getAndroidResourceIdentifier(asset);
   return drawbleFolder + '/' + fileName + '.' + asset.type;
 }
 
@@ -151,7 +151,7 @@ class AssetSourceResolver {
 
   static pickScale(scales: Array<number>, deviceScale: number): number {
     // Packager guarantees that `scales` array is sorted
-    for (var i = 0; i < scales.length; i++) {
+    for (let i = 0; i < scales.length; i++) {
       if (scales[i] >= deviceScale) {
         return scales[i];
       }

Libraries/Image/Image.android.js

@@ -10,25 +10,25 @@
 
 'use strict';
 
-var ImageResizeMode = require('ImageResizeMode');
+const ImageResizeMode = require('ImageResizeMode');
-var ImageStylePropTypes = require('ImageStylePropTypes');
+const ImageStylePropTypes = require('ImageStylePropTypes');
-var NativeMethodsMixin = require('NativeMethodsMixin');
+const NativeMethodsMixin = require('NativeMethodsMixin');
-var NativeModules = require('NativeModules');
+const NativeModules = require('NativeModules');
-var React = require('React');
+const React = require('React');
-var PropTypes = require('prop-types');
+const PropTypes = require('prop-types');
-var ReactNativeViewAttributes = require('ReactNativeViewAttributes');
+const ReactNativeViewAttributes = require('ReactNativeViewAttributes');
-var StyleSheet = require('StyleSheet');
+const StyleSheet = require('StyleSheet');
-var StyleSheetPropType = require('StyleSheetPropType');
+const StyleSheetPropType = require('StyleSheetPropType');
 const TextAncestor = require('TextAncestor');
-var ViewPropTypes = require('ViewPropTypes');
+const ViewPropTypes = require('ViewPropTypes');
 
-var createReactClass = require('create-react-class');
+const createReactClass = require('create-react-class');
-var flattenStyle = require('flattenStyle');
+const flattenStyle = require('flattenStyle');
-var merge = require('merge');
+const merge = require('merge');
-var requireNativeComponent = require('requireNativeComponent');
+const requireNativeComponent = require('requireNativeComponent');
-var resolveAssetSource = require('resolveAssetSource');
+const resolveAssetSource = require('resolveAssetSource');
 
-var {ImageLoader} = NativeModules;
+const {ImageLoader} = NativeModules;
 
 let _requestId = 1;
 function generateRequestId() {
@@ -42,7 +42,7 @@ function generateRequestId() {
  *
  * See https://facebook.github.io/react-native/docs/image.html
  */
-var Image = createReactClass({
+const Image = createReactClass({
   displayName: 'Image',
   propTypes: {
     ...ViewPropTypes,
@@ -275,13 +275,13 @@ var Image = createReactClass({
   },
 });
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   base: {
     overflow: 'hidden',
   },
 });
 
-var cfg = {
+const cfg = {
   nativeOnly: {
     src: true,
     headers: true,
@@ -290,8 +290,8 @@ var cfg = {
     shouldNotifyLoadEvents: true,
   },
 };
-var RKImage = requireNativeComponent('RCTImageView', Image, cfg);
+const RKImage = requireNativeComponent('RCTImageView', Image, cfg);
-var RCTTextInlineImage = requireNativeComponent(
+const RCTTextInlineImage = requireNativeComponent(
   'RCTTextInlineImage',
   Image,
   cfg,

Libraries/Image/ImageResizeMode.js

@@ -12,13 +12,13 @@
 /* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an error
  * found when Flow v0.54 was deployed. To see the error delete this comment and
  * run Flow. */
-var keyMirror = require('fbjs/lib/keyMirror');
+const keyMirror = require('fbjs/lib/keyMirror');
 
 /**
  * ImageResizeMode - Enum for different image resizing modes, set via
  * `resizeMode` style property on `<Image>` components.
  */
-var ImageResizeMode = keyMirror({
+const ImageResizeMode = keyMirror({
   /**
    * contain - The image will be resized such that it will be completely
    * visible, contained within the frame of the View.

Libraries/Image/ImageStylePropTypes.js

@@ -9,14 +9,14 @@
  */
 'use strict';
 
-var ColorPropType = require('ColorPropType');
+const ColorPropType = require('ColorPropType');
-var ImageResizeMode = require('ImageResizeMode');
+const ImageResizeMode = require('ImageResizeMode');
-var LayoutPropTypes = require('LayoutPropTypes');
+const LayoutPropTypes = require('LayoutPropTypes');
-var ReactPropTypes = require('prop-types');
+const ReactPropTypes = require('prop-types');
-var ShadowPropTypesIOS = require('ShadowPropTypesIOS');
+const ShadowPropTypesIOS = require('ShadowPropTypesIOS');
-var TransformPropTypes = require('TransformPropTypes');
+const TransformPropTypes = require('TransformPropTypes');
 
-var ImageStylePropTypes = {
+const ImageStylePropTypes = {
   ...LayoutPropTypes,
   ...ShadowPropTypesIOS,
   ...TransformPropTypes,

Libraries/Image/RelativeImageStub.js

@@ -11,7 +11,7 @@
 // This is a stub for flow to make it understand require('./icon.png')
 // See metro/src/Bundler/index.js
 
-var AssetRegistry = require('AssetRegistry');
+const AssetRegistry = require('AssetRegistry');
 
 module.exports = AssetRegistry.registerAsset({
   __packager_asset: true,

Libraries/Image/__tests__/resolveAssetSource-test.js

@@ -8,13 +8,13 @@
  */
 'use strict';
 
-var AssetRegistry = require('AssetRegistry');
+const AssetRegistry = require('AssetRegistry');
-var Platform = require('Platform');
+const Platform = require('Platform');
-var NativeModules = require('NativeModules');
+const NativeModules = require('NativeModules');
-var resolveAssetSource = require('../resolveAssetSource');
+const resolveAssetSource = require('../resolveAssetSource');
 
 function expectResolvesAsset(input, expectedSource) {
-  var assetId = AssetRegistry.registerAsset(input);
+  const assetId = AssetRegistry.registerAsset(input);
   expect(resolveAssetSource(assetId)).toEqual(expectedSource);
 }
 
@@ -24,10 +24,10 @@ describe('resolveAssetSource', () => {
   });
 
   it('returns same source for simple static and network images', () => {
-    var source1 = {uri: 'https://www.facebook.com/logo'};
+    const source1 = {uri: 'https://www.facebook.com/logo'};
     expect(resolveAssetSource(source1)).toBe(source1);
 
-    var source2 = {uri: 'logo'};
+    const source2 = {uri: 'logo'};
     expect(resolveAssetSource(source2)).toBe(source2);
   });
 

Libraries/Image/resolveAssetSource.js

@@ -85,7 +85,7 @@ function resolveAssetSource(source: any): ?ResolvedAssetSource {
     return source;
   }
 
-  var asset = AssetRegistry.getAssetByID(source);
+  const asset = AssetRegistry.getAssetByID(source);
   if (!asset) {
     return null;
   }

Libraries/Inspector/BorderBox.js

@@ -8,16 +8,16 @@
  */
 'use strict';
 
-var React = require('React');
+const React = require('React');
-var View = require('View');
+const View = require('View');
 
 class BorderBox extends React.Component<$FlowFixMeProps> {
   render() {
-    var box = this.props.box;
+    const box = this.props.box;
     if (!box) {
       return this.props.children;
     }
-    var style = {
+    const style = {
       borderTopWidth: box.top,
       borderBottomWidth: box.bottom,
       borderLeftWidth: box.left,

Libraries/Inspector/BoxInspector.js

@@ -8,13 +8,13 @@
  */
 'use strict';
 
-var React = require('React');
+const React = require('React');
-var StyleSheet = require('StyleSheet');
+const StyleSheet = require('StyleSheet');
-var Text = require('Text');
+const Text = require('Text');
-var View = require('View');
+const View = require('View');
-var resolveBoxStyle = require('resolveBoxStyle');
+const resolveBoxStyle = require('resolveBoxStyle');
 
-var blank = {
+const blank = {
   top: 0,
   left: 0,
   right: 0,
@@ -23,10 +23,10 @@ var blank = {
 
 class BoxInspector extends React.Component<$FlowFixMeProps> {
   render() {
-    var frame = this.props.frame;
+    const frame = this.props.frame;
-    var style = this.props.style;
+    const style = this.props.style;
-    var margin = style && resolveBoxStyle('margin', style) || blank;
+    const margin = style && resolveBoxStyle('margin', style) || blank;
-    var padding = style && resolveBoxStyle('padding', style) || blank;
+    const padding = style && resolveBoxStyle('padding', style) || blank;
     return (
       <BoxContainer title="margin" titleStyle={styles.marginLabel} box={margin}>
         <BoxContainer title="padding" box={padding}>
@@ -46,7 +46,7 @@ class BoxInspector extends React.Component<$FlowFixMeProps> {
 
 class BoxContainer extends React.Component<$FlowFixMeProps> {
   render() {
-    var box = this.props.box;
+    const box = this.props.box;
     return (
       <View style={styles.box}>
         <View style={styles.row}>
@@ -66,7 +66,7 @@ class BoxContainer extends React.Component<$FlowFixMeProps> {
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   row: {
     flexDirection: 'row',
     alignItems: 'center',

Libraries/Inspector/ElementBox.js

@@ -8,20 +8,20 @@
  */
 'use strict';
 
-var React = require('React');
+const React = require('React');
-var View = require('View');
+const View = require('View');
-var StyleSheet = require('StyleSheet');
+const StyleSheet = require('StyleSheet');
-var BorderBox = require('BorderBox');
+const BorderBox = require('BorderBox');
-var resolveBoxStyle = require('resolveBoxStyle');
+const resolveBoxStyle = require('resolveBoxStyle');
 
-var flattenStyle = require('flattenStyle');
+const flattenStyle = require('flattenStyle');
 
 class ElementBox extends React.Component<$FlowFixMeProps> {
   render() {
-    var style = flattenStyle(this.props.style) || {};
+    const style = flattenStyle(this.props.style) || {};
-    var margin = resolveBoxStyle('margin', style);
+    const margin = resolveBoxStyle('margin', style);
-    var padding = resolveBoxStyle('padding', style);
+    const padding = resolveBoxStyle('padding', style);
-    var frameStyle = this.props.frame;
+    let frameStyle = this.props.frame;
     if (margin) {
       frameStyle = {
         top: frameStyle.top - margin.top,
@@ -30,7 +30,7 @@ class ElementBox extends React.Component<$FlowFixMeProps> {
         width: frameStyle.width + margin.left + margin.right,
       };
     }
-    var contentStyle = {
+    let contentStyle = {
       width: this.props.frame.width,
       height: this.props.frame.height,
     };
@@ -52,7 +52,7 @@ class ElementBox extends React.Component<$FlowFixMeProps> {
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   frame: {
     position: 'absolute',
   },

Libraries/Inspector/InspectorOverlay.js

@@ -8,13 +8,13 @@
  */
 'use strict';
 
-var Dimensions = require('Dimensions');
+const Dimensions = require('Dimensions');
-var ElementBox = require('ElementBox');
+const ElementBox = require('ElementBox');
-var PropTypes = require('prop-types');
+const PropTypes = require('prop-types');
-var React = require('React');
+const React = require('React');
-var StyleSheet = require('StyleSheet');
+const StyleSheet = require('StyleSheet');
-var UIManager = require('UIManager');
+const UIManager = require('UIManager');
-var View = require('View');
+const View = require('View');
 
 type EventLike = {
   nativeEvent: Object,
@@ -38,7 +38,7 @@ class InspectorOverlay extends React.Component<{
   };
 
   findViewForTouchEvent = (e: EventLike) => {
-    var {locationX, locationY} = e.nativeEvent.touches[0];
+    const {locationX, locationY} = e.nativeEvent.touches[0];
     UIManager.findSubviewIn(
       this.props.inspectedViewTag,
       [locationX, locationY],
@@ -54,7 +54,7 @@ class InspectorOverlay extends React.Component<{
   };
 
   render() {
-    var content = null;
+    let content = null;
     if (this.props.inspected) {
       content = <ElementBox frame={this.props.inspected.frame} style={this.props.inspected.style} />;
     }
@@ -70,7 +70,7 @@ class InspectorOverlay extends React.Component<{
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   inspector: {
     backgroundColor: 'transparent',
     position: 'absolute',

Libraries/Inspector/PerformanceOverlay.js

@@ -8,20 +8,20 @@
  */
 'use strict';
 
-var PerformanceLogger = require('PerformanceLogger');
+const PerformanceLogger = require('PerformanceLogger');
-var React = require('React');
+const React = require('React');
-var StyleSheet = require('StyleSheet');
+const StyleSheet = require('StyleSheet');
-var Text = require('Text');
+const Text = require('Text');
-var View = require('View');
+const View = require('View');
 
 class PerformanceOverlay extends React.Component<{}> {
   render() {
-    var perfLogs = PerformanceLogger.getTimespans();
+    const perfLogs = PerformanceLogger.getTimespans();
-    var items = [];
+    const items = [];
 
-    for (var key in perfLogs) {
+    for (const key in perfLogs) {
       if (perfLogs[key].totalTime) {
-        var unit = (key === 'BundleSize') ? 'b' : 'ms';
+        const unit = (key === 'BundleSize') ? 'b' : 'ms';
         items.push(
           <View style={styles.row} key={key}>
             <Text style={[styles.text, styles.label]}>{key}</Text>
@@ -41,7 +41,7 @@ class PerformanceOverlay extends React.Component<{}> {
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   container: {
     height: 100,
     paddingTop: 10,

Libraries/Inspector/StyleInspector.js

@@ -8,17 +8,17 @@
  */
 'use strict';
 
-var React = require('React');
+const React = require('React');
-var StyleSheet = require('StyleSheet');
+const StyleSheet = require('StyleSheet');
-var Text = require('Text');
+const Text = require('Text');
-var View = require('View');
+const View = require('View');
 
 class StyleInspector extends React.Component<$FlowFixMeProps> {
   render() {
     if (!this.props.style) {
       return <Text style={styles.noStyle}>No style</Text>;
     }
-    var names = Object.keys(this.props.style);
+    const names = Object.keys(this.props.style);
     return (
       <View style={styles.container}>
         <View>
@@ -27,7 +27,7 @@ class StyleInspector extends React.Component<$FlowFixMeProps> {
 
         <View>
           {names.map(name => {
-            var value = typeof this.props.style[name] === 'object' ? JSON.stringify(this.props.style[name]) : this.props.style[name];
+            const value = typeof this.props.style[name] === 'object' ? JSON.stringify(this.props.style[name]) : this.props.style[name];
             return <Text key={name} style={styles.value}>{value}</Text>;
           } ) }
         </View>
@@ -36,7 +36,7 @@ class StyleInspector extends React.Component<$FlowFixMeProps> {
   }
 }
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   container: {
     flexDirection: 'row',
   },

Libraries/Inspector/resolveBoxStyle.js

@@ -18,9 +18,9 @@
  * If none are set, returns false.
  */
 function resolveBoxStyle(prefix: string, style: Object): ?Object {
-  var res = {};
+  const res = {};
-  var subs = ['top', 'left', 'bottom', 'right'];
+  const subs = ['top', 'left', 'bottom', 'right'];
-  var set = false;
+  let set = false;
   subs.forEach(sub => {
     res[sub] = style[prefix] || 0;
   });
@@ -36,7 +36,7 @@ function resolveBoxStyle(prefix: string, style: Object): ?Object {
     set = true;
   }
   subs.forEach(sub => {
-    var val = style[prefix + capFirst(sub)];
+    const val = style[prefix + capFirst(sub)];
     if (val) {
       res[sub] = val;
       set = true;

Libraries/Interaction/InteractionManager.js

@@ -77,7 +77,7 @@ const DEBUG = false;
  * allowing events such as touches to start interactions and block queued tasks
  * from executing, making apps more responsive.
  */
-var InteractionManager = {
+const InteractionManager = {
   Events: keyMirror({
     interactionStart: true,
     interactionComplete: true,
@@ -118,7 +118,7 @@ var InteractionManager = {
   createInteractionHandle(): Handle {
     DEBUG && infoLog('create interaction handle');
     _scheduleUpdate();
-    var handle = ++_inc;
+    const handle = ++_inc;
     _addInteractionSet.add(handle);
     return handle;
   },
@@ -181,14 +181,14 @@ function _scheduleUpdate() {
 function _processUpdate() {
   _nextUpdateHandle = 0;
 
-  var interactionCount = _interactionSet.size;
+  const interactionCount = _interactionSet.size;
   _addInteractionSet.forEach(handle =>
     _interactionSet.add(handle)
   );
   _deleteInteractionSet.forEach(handle =>
     _interactionSet.delete(handle)
   );
-  var nextInteractionCount = _interactionSet.size;
+  const nextInteractionCount = _interactionSet.size;
 
   if (interactionCount !== 0 && nextInteractionCount === 0) {
     // transition from 1+ --> 0 interactions

Libraries/Interaction/InteractionMixin.js

@@ -8,14 +8,14 @@
  */
 'use strict';
 
-var InteractionManager = require('InteractionManager');
+const InteractionManager = require('InteractionManager');
 
 /**
  * This mixin provides safe versions of InteractionManager start/end methods
  * that ensures `clearInteractionHandle` is always called
  * once per start, even if the component is unmounted.
  */
-var InteractionMixin = {
+const InteractionMixin = {
   componentWillUnmount: function() {
     while (this._interactionMixinHandles.length) {
       InteractionManager.clearInteractionHandle(
@@ -27,7 +27,7 @@ var InteractionMixin = {
   _interactionMixinHandles: ([]: Array<number>),
 
   createInteractionHandle: function() {
-    var handle = InteractionManager.createInteractionHandle();
+    const handle = InteractionManager.createInteractionHandle();
     this._interactionMixinHandles.push(handle);
     return handle;
   },

Libraries/Interaction/__tests__/InteractionMixin-test.js

@@ -11,9 +11,9 @@
 jest.enableAutomock().unmock('InteractionMixin');
 
 describe('InteractionMixin', () => {
-  var InteractionManager;
+  let InteractionManager;
-  var InteractionMixin;
+  let InteractionMixin;
-  var component;
+  let component;
 
   beforeEach(() => {
     jest.resetModules();
@@ -29,19 +29,19 @@ describe('InteractionMixin', () => {
   });
 
   it('should end interactions', () => {
-    var handle = {};
+    const handle = {};
     component.clearInteractionHandle(handle);
     expect(InteractionManager.clearInteractionHandle).toBeCalledWith(handle);
   });
 
   it('should schedule tasks', () => {
-    var task = jest.fn();
+    const task = jest.fn();
     component.runAfterInteractions(task);
     expect(InteractionManager.runAfterInteractions).toBeCalledWith(task);
   });
 
   it('should end unfinished interactions in componentWillUnmount', () => {
-    var handle = component.createInteractionHandle();
+    const handle = component.createInteractionHandle();
     component.componentWillUnmount();
     expect(InteractionManager.clearInteractionHandle).toBeCalledWith(handle);
   });

Libraries/Lists/ListView/ListView.js

@@ -9,34 +9,34 @@
  */
 'use strict';
 
-var ListViewDataSource = require('ListViewDataSource');
+const ListViewDataSource = require('ListViewDataSource');
-var Platform = require('Platform');
+const Platform = require('Platform');
-var React = require('React');
+const React = require('React');
-var PropTypes = require('prop-types');
+const PropTypes = require('prop-types');
-var ReactNative = require('ReactNative');
+const ReactNative = require('ReactNative');
-var RCTScrollViewManager = require('NativeModules').ScrollViewManager;
+const RCTScrollViewManager = require('NativeModules').ScrollViewManager;
-var ScrollView = require('ScrollView');
+const ScrollView = require('ScrollView');
-var ScrollResponder = require('ScrollResponder');
+const ScrollResponder = require('ScrollResponder');
-var StaticRenderer = require('StaticRenderer');
+const StaticRenderer = require('StaticRenderer');
 /* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an error
  * found when Flow v0.54 was deployed. To see the error delete this comment and
  * run Flow. */
-var TimerMixin = require('react-timer-mixin');
+const TimerMixin = require('react-timer-mixin');
-var View = require('View');
+const View = require('View');
 
 /* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an error
  * found when Flow v0.54 was deployed. To see the error delete this comment and
  * run Flow. */
-var cloneReferencedElement = require('react-clone-referenced-element');
+const cloneReferencedElement = require('react-clone-referenced-element');
-var createReactClass = require('create-react-class');
+const createReactClass = require('create-react-class');
-var isEmpty = require('isEmpty');
+const isEmpty = require('isEmpty');
-var merge = require('merge');
+const merge = require('merge');
 
-var DEFAULT_PAGE_SIZE = 1;
+const DEFAULT_PAGE_SIZE = 1;
-var DEFAULT_INITIAL_ROWS = 10;
+const DEFAULT_INITIAL_ROWS = 10;
-var DEFAULT_SCROLL_RENDER_AHEAD = 1000;
+const DEFAULT_SCROLL_RENDER_AHEAD = 1000;
-var DEFAULT_END_REACHED_THRESHOLD = 1000;
+const DEFAULT_END_REACHED_THRESHOLD = 1000;
-var DEFAULT_SCROLL_CALLBACK_THROTTLE = 50;
+const DEFAULT_SCROLL_CALLBACK_THROTTLE = 50;
 
 /**
  * DEPRECATED - use one of the new list components, such as [`FlatList`](docs/flatlist.html)
@@ -95,7 +95,7 @@ var DEFAULT_SCROLL_CALLBACK_THROTTLE = 50;
  *    rendering rows.
  */
 
-var ListView = createReactClass({
+const ListView = createReactClass({
   displayName: 'ListView',
   _childFrames: ([]: Array<Object>),
   _sentEndForContentLength: (null: ?number),
@@ -405,28 +405,28 @@ var ListView = createReactClass({
   },
 
   render: function() {
-    var bodyComponents = [];
+    const bodyComponents = [];
 
-    var dataSource = this.props.dataSource;
+    const dataSource = this.props.dataSource;
-    var allRowIDs = dataSource.rowIdentities;
+    const allRowIDs = dataSource.rowIdentities;
-    var rowCount = 0;
+    let rowCount = 0;
-    var stickySectionHeaderIndices = [];
+    const stickySectionHeaderIndices = [];
 
     const {renderSectionHeader} = this.props;
 
-    var header = this.props.renderHeader && this.props.renderHeader();
+    const header = this.props.renderHeader && this.props.renderHeader();
-    var footer = this.props.renderFooter && this.props.renderFooter();
+    const footer = this.props.renderFooter && this.props.renderFooter();
-    var totalIndex = header ? 1 : 0;
+    let totalIndex = header ? 1 : 0;
 
-    for (var sectionIdx = 0; sectionIdx < allRowIDs.length; sectionIdx++) {
+    for (let sectionIdx = 0; sectionIdx < allRowIDs.length; sectionIdx++) {
-      var sectionID = dataSource.sectionIdentities[sectionIdx];
+      const sectionID = dataSource.sectionIdentities[sectionIdx];
-      var rowIDs = allRowIDs[sectionIdx];
+      const rowIDs = allRowIDs[sectionIdx];
       if (rowIDs.length === 0) {
         if (this.props.enableEmptySections === undefined) {
           /* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses
            * an error found when Flow v0.54 was deployed. To see the error
            * delete this comment and run Flow. */
-          var warning = require('fbjs/lib/warning');
+          const warning = require('fbjs/lib/warning');
           warning(
             false,
             'In next release empty section headers will be rendered.' +
@@ -434,7 +434,7 @@ var ListView = createReactClass({
           );
           continue;
         } else {
-          var invariant = require('fbjs/lib/invariant');
+          const invariant = require('fbjs/lib/invariant');
           invariant(
             this.props.enableEmptySections,
             "In next release 'enableEmptySections' flag will be deprecated, empty section headers will always be rendered." +
@@ -460,13 +460,13 @@ var ListView = createReactClass({
         }
       }
 
-      for (var rowIdx = 0; rowIdx < rowIDs.length; rowIdx++) {
+      for (let rowIdx = 0; rowIdx < rowIDs.length; rowIdx++) {
-        var rowID = rowIDs[rowIdx];
+        const rowID = rowIDs[rowIdx];
-        var comboID = sectionID + '_' + rowID;
+        const comboID = sectionID + '_' + rowID;
-        var shouldUpdateRow =
+        const shouldUpdateRow =
           rowCount >= this._prevRenderedRowsCount &&
           dataSource.rowShouldUpdate(sectionIdx, rowIdx);
-        var row = (
+        const row = (
           <StaticRenderer
             key={'r_' + comboID}
             shouldUpdate={!!shouldUpdateRow}
@@ -486,11 +486,11 @@ var ListView = createReactClass({
           this.props.renderSeparator &&
           (rowIdx !== rowIDs.length - 1 || sectionIdx === allRowIDs.length - 1)
         ) {
-          var adjacentRowHighlighted =
+          const adjacentRowHighlighted =
             this.state.highlightedRow.sectionID === sectionID &&
             (this.state.highlightedRow.rowID === rowID ||
               this.state.highlightedRow.rowID === rowIDs[rowIdx + 1]);
-          var separator = this.props.renderSeparator(
+          const separator = this.props.renderSeparator(
             sectionID,
             rowID,
             adjacentRowHighlighted,
@@ -509,7 +509,7 @@ var ListView = createReactClass({
       }
     }
 
-    var {renderScrollComponent, ...props} = this.props;
+    const {renderScrollComponent, ...props} = this.props;
     if (!props.scrollEventThrottle) {
       props.scrollEventThrottle = DEFAULT_SCROLL_CALLBACK_THROTTLE;
     }
@@ -550,7 +550,7 @@ var ListView = createReactClass({
    */
 
   _measureAndUpdateScrollProps: function() {
-    var scrollComponent = this.getScrollResponder();
+    const scrollComponent = this.getScrollResponder();
     if (!scrollComponent || !scrollComponent.getInnerViewNode) {
       return;
     }
@@ -570,7 +570,7 @@ var ListView = createReactClass({
   },
 
   _onContentSizeChange: function(width: number, height: number) {
-    var contentLength = !this.props.horizontal ? height : width;
+    const contentLength = !this.props.horizontal ? height : width;
     if (contentLength !== this.scrollProperties.contentLength) {
       this.scrollProperties.contentLength = contentLength;
       this._updateVisibleRows();
@@ -581,8 +581,8 @@ var ListView = createReactClass({
   },
 
   _onLayout: function(event: Object) {
-    var {width, height} = event.nativeEvent.layout;
+    const {width, height} = event.nativeEvent.layout;
-    var visibleLength = !this.props.horizontal ? height : width;
+    const visibleLength = !this.props.horizontal ? height : width;
     if (visibleLength !== this.scrollProperties.visibleLength) {
       this.scrollProperties.visibleLength = visibleLength;
       this._updateVisibleRows();
@@ -622,7 +622,7 @@ var ListView = createReactClass({
       return;
     }
 
-    var distanceFromEnd = this._getDistanceFromEnd(this.scrollProperties);
+    const distanceFromEnd = this._getDistanceFromEnd(this.scrollProperties);
     if (distanceFromEnd < this.props.scrollRenderAheadDistance) {
       this._pageInNewRows();
     }
@@ -631,7 +631,7 @@ var ListView = createReactClass({
   _pageInNewRows: function() {
     this.setState(
       (state, props) => {
-        var rowsToRender = Math.min(
+        const rowsToRender = Math.min(
           state.curRenderedRowsCount + props.pageSize,
           props.enableEmptySections
             ? props.dataSource.getRowAndSectionCount()
@@ -666,32 +666,32 @@ var ListView = createReactClass({
         this._childFrames[newFrame.index] = merge(newFrame);
       });
     }
-    var isVertical = !this.props.horizontal;
+    const isVertical = !this.props.horizontal;
-    var dataSource = this.props.dataSource;
+    const dataSource = this.props.dataSource;
-    var visibleMin = this.scrollProperties.offset;
+    const visibleMin = this.scrollProperties.offset;
-    var visibleMax = visibleMin + this.scrollProperties.visibleLength;
+    const visibleMax = visibleMin + this.scrollProperties.visibleLength;
-    var allRowIDs = dataSource.rowIdentities;
+    const allRowIDs = dataSource.rowIdentities;
 
-    var header = this.props.renderHeader && this.props.renderHeader();
+    const header = this.props.renderHeader && this.props.renderHeader();
-    var totalIndex = header ? 1 : 0;
+    let totalIndex = header ? 1 : 0;
-    var visibilityChanged = false;
+    let visibilityChanged = false;
-    var changedRows = {};
+    const changedRows = {};
-    for (var sectionIdx = 0; sectionIdx < allRowIDs.length; sectionIdx++) {
+    for (let sectionIdx = 0; sectionIdx < allRowIDs.length; sectionIdx++) {
-      var rowIDs = allRowIDs[sectionIdx];
+      const rowIDs = allRowIDs[sectionIdx];
       if (rowIDs.length === 0) {
         continue;
       }
-      var sectionID = dataSource.sectionIdentities[sectionIdx];
+      const sectionID = dataSource.sectionIdentities[sectionIdx];
       if (this.props.renderSectionHeader) {
         totalIndex++;
       }
-      var visibleSection = this._visibleRows[sectionID];
+      let visibleSection = this._visibleRows[sectionID];
       if (!visibleSection) {
         visibleSection = {};
       }
-      for (var rowIdx = 0; rowIdx < rowIDs.length; rowIdx++) {
+      for (let rowIdx = 0; rowIdx < rowIDs.length; rowIdx++) {
-        var rowID = rowIDs[rowIdx];
+        const rowID = rowIDs[rowIdx];
-        var frame = this._childFrames[totalIndex];
+        const frame = this._childFrames[totalIndex];
         totalIndex++;
         if (
           this.props.renderSeparator &&
@@ -702,9 +702,9 @@ var ListView = createReactClass({
         if (!frame) {
           break;
         }
-        var rowVisible = visibleSection[rowID];
+        const rowVisible = visibleSection[rowID];
-        var min = isVertical ? frame.y : frame.x;
+        const min = isVertical ? frame.y : frame.x;
-        var max = min + (isVertical ? frame.height : frame.width);
+        const max = min + (isVertical ? frame.height : frame.width);
         if ((!min && !max) || min === max) {
           break;
         }
@@ -737,7 +737,7 @@ var ListView = createReactClass({
   },
 
   _onScroll: function(e: Object) {
-    var isVertical = !this.props.horizontal;
+    const isVertical = !this.props.horizontal;
     this.scrollProperties.visibleLength =
       e.nativeEvent.layoutMeasurement[isVertical ? 'height' : 'width'];
     this.scrollProperties.contentLength =

Libraries/Lists/ListView/ListViewDataSource.js

@@ -9,12 +9,12 @@
  */
 'use strict';
 
-var invariant = require('fbjs/lib/invariant');
+const invariant = require('fbjs/lib/invariant');
-var isEmpty = require('isEmpty');
+const isEmpty = require('isEmpty');
 /* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an error
  * found when Flow v0.54 was deployed. To see the error delete this comment and
  * run Flow. */
-var warning = require('fbjs/lib/warning');
+const warning = require('fbjs/lib/warning');
 
 function defaultGetRowData(
   dataBlob: any,
@@ -142,7 +142,7 @@ class ListViewDataSource {
     dataBlob: $ReadOnlyArray<any> | {+[key: string]: any},
     rowIdentities: ?$ReadOnlyArray<string>,
   ): ListViewDataSource {
-    var rowIds = rowIdentities ? [[...rowIdentities]] : null;
+    const rowIds = rowIdentities ? [[...rowIdentities]] : null;
     if (!this._sectionHeaderHasChanged) {
       this._sectionHeaderHasChanged = () => false;
     }
@@ -184,7 +184,7 @@ class ListViewDataSource {
       'row and section ids lengths must be the same',
     );
 
-    var newSource = new ListViewDataSource({
+    const newSource = new ListViewDataSource({
       getRowData: this._getRowData,
       getSectionHeaderData: this._getSectionHeaderData,
       rowHasChanged: this._rowHasChanged,
@@ -237,7 +237,7 @@ class ListViewDataSource {
    * Returns if the row is dirtied and needs to be rerendered
    */
   rowShouldUpdate(sectionIndex: number, rowIndex: number): boolean {
-    var needsUpdate = this._dirtyRows[sectionIndex][rowIndex];
+    const needsUpdate = this._dirtyRows[sectionIndex][rowIndex];
     warning(
       needsUpdate !== undefined,
       'missing dirtyBit for section, row: ' + sectionIndex + ', ' + rowIndex,
@@ -249,8 +249,8 @@ class ListViewDataSource {
    * Gets the data required to render the row.
    */
   getRowData(sectionIndex: number, rowIndex: number): any {
-    var sectionID = this.sectionIdentities[sectionIndex];
+    const sectionID = this.sectionIdentities[sectionIndex];
-    var rowID = this.rowIdentities[sectionIndex][rowIndex];
+    const rowID = this.rowIdentities[sectionIndex][rowIndex];
     warning(
       sectionID !== undefined && rowID !== undefined,
       'rendering invalid section, row: ' + sectionIndex + ', ' + rowIndex,
@@ -263,8 +263,8 @@ class ListViewDataSource {
    * or null of out of range indexes.
    */
   getRowIDForFlatIndex(index: number): ?string {
-    var accessIndex = index;
+    let accessIndex = index;
-    for (var ii = 0; ii < this.sectionIdentities.length; ii++) {
+    for (let ii = 0; ii < this.sectionIdentities.length; ii++) {
       if (accessIndex >= this.rowIdentities[ii].length) {
         accessIndex -= this.rowIdentities[ii].length;
       } else {
@@ -279,8 +279,8 @@ class ListViewDataSource {
    * or null for out of range indexes.
    */
   getSectionIDForFlatIndex(index: number): ?string {
-    var accessIndex = index;
+    let accessIndex = index;
-    for (var ii = 0; ii < this.sectionIdentities.length; ii++) {
+    for (let ii = 0; ii < this.sectionIdentities.length; ii++) {
       if (accessIndex >= this.rowIdentities[ii].length) {
         accessIndex -= this.rowIdentities[ii].length;
       } else {
@@ -294,8 +294,8 @@ class ListViewDataSource {
    * Returns an array containing the number of rows in each section
    */
   getSectionLengths(): Array<number> {
-    var results = [];
+    const results = [];
-    for (var ii = 0; ii < this.sectionIdentities.length; ii++) {
+    for (let ii = 0; ii < this.sectionIdentities.length; ii++) {
       results.push(this.rowIdentities[ii].length);
     }
     return results;
@@ -305,7 +305,7 @@ class ListViewDataSource {
    * Returns if the section header is dirtied and needs to be rerendered
    */
   sectionHeaderShouldUpdate(sectionIndex: number): boolean {
-    var needsUpdate = this._dirtySections[sectionIndex];
+    const needsUpdate = this._dirtySections[sectionIndex];
     warning(
       needsUpdate !== undefined,
       'missing dirtyBit for section: ' + sectionIndex,
@@ -320,7 +320,7 @@ class ListViewDataSource {
     if (!this._getSectionHeaderData) {
       return null;
     }
-    var sectionID = this.sectionIdentities[sectionIndex];
+    const sectionID = this.sectionIdentities[sectionIndex];
     warning(
       sectionID !== undefined,
       'renderSection called on invalid section: ' + sectionIndex,
@@ -353,9 +353,9 @@ class ListViewDataSource {
     prevRowIDs: Array<Array<string>>,
   ): void {
     // construct a hashmap of the existing (old) id arrays
-    var prevSectionsHash = keyedDictionaryFromArray(prevSectionIDs);
+    const prevSectionsHash = keyedDictionaryFromArray(prevSectionIDs);
-    var prevRowsHash = {};
+    const prevRowsHash = {};
-    for (var ii = 0; ii < prevRowIDs.length; ii++) {
+    for (let ii = 0; ii < prevRowIDs.length; ii++) {
       var sectionID = prevSectionIDs[ii];
       warning(
         !prevRowsHash[sectionID],
@@ -368,12 +368,12 @@ class ListViewDataSource {
     this._dirtySections = [];
     this._dirtyRows = [];
 
-    var dirty;
+    let dirty;
-    for (var sIndex = 0; sIndex < this.sectionIdentities.length; sIndex++) {
+    for (let sIndex = 0; sIndex < this.sectionIdentities.length; sIndex++) {
       var sectionID = this.sectionIdentities[sIndex];
       // dirty if the sectionHeader is new or _sectionHasChanged is true
       dirty = !prevSectionsHash[sectionID];
-      var sectionHeaderHasChanged = this._sectionHeaderHasChanged;
+      const sectionHeaderHasChanged = this._sectionHeaderHasChanged;
       if (!dirty && sectionHeaderHasChanged) {
         dirty = sectionHeaderHasChanged(
           this._getSectionHeaderData(prevDataBlob, sectionID),
@@ -384,11 +384,11 @@ class ListViewDataSource {
 
       this._dirtyRows[sIndex] = [];
       for (
-        var rIndex = 0;
+        let rIndex = 0;
         rIndex < this.rowIdentities[sIndex].length;
         rIndex++
       ) {
-        var rowID = this.rowIdentities[sIndex][rIndex];
+        const rowID = this.rowIdentities[sIndex][rIndex];
         // dirty if the section is new, row is new or _rowHasChanged is true
         dirty =
           !prevSectionsHash[sectionID] ||
@@ -404,9 +404,9 @@ class ListViewDataSource {
 }
 
 function countRows(allRowIDs) {
-  var totalRows = 0;
+  let totalRows = 0;
-  for (var sectionIdx = 0; sectionIdx < allRowIDs.length; sectionIdx++) {
+  for (let sectionIdx = 0; sectionIdx < allRowIDs.length; sectionIdx++) {
-    var rowIDs = allRowIDs[sectionIdx];
+    const rowIDs = allRowIDs[sectionIdx];
     totalRows += rowIDs.length;
   }
   return totalRows;
@@ -416,9 +416,9 @@ function keyedDictionaryFromArray(arr) {
   if (isEmpty(arr)) {
     return {};
   }
-  var result = {};
+  const result = {};
-  for (var ii = 0; ii < arr.length; ii++) {
+  for (let ii = 0; ii < arr.length; ii++) {
-    var key = arr[ii];
+    const key = arr[ii];
     warning(!result[key], 'Value appears more than once in array: ' + key);
     result[key] = true;
   }

Libraries/Modal/Modal.js

@@ -36,7 +36,7 @@ import type EmitterSubscription from 'EmitterSubscription';
 // <Modal> on screen. There can be different ones, either nested or as siblings.
 // We cannot pass the onDismiss callback to native as the view will be
 // destroyed before the callback is fired.
-var uniqueModalIdentifier = 0;
+let uniqueModalIdentifier = 0;
 
 class Modal extends React.Component<Object> {
   static propTypes = {

Libraries/Network/FormData.js

@@ -60,9 +60,9 @@ class FormData {
 
   getParts(): Array<FormDataPart> {
     return this._parts.map(([name, value]) => {
-      var contentDisposition = 'form-data; name="' + name + '"';
+      const contentDisposition = 'form-data; name="' + name + '"';
 
-      var headers: Headers = {'content-disposition': contentDisposition};
+      const headers: Headers = {'content-disposition': contentDisposition};
 
       // The body part is a "blob", which in React Native just means
       // an object with a `uri` attribute. Optionally, it can also

Libraries/Network/XHRInterceptor.js

@@ -12,13 +12,13 @@ const originalXHROpen = XMLHttpRequest.prototype.open;
 const originalXHRSend = XMLHttpRequest.prototype.send;
 const originalXHRSetRequestHeader = XMLHttpRequest.prototype.setRequestHeader;
 
-var openCallback;
+let openCallback;
-var sendCallback;
+let sendCallback;
-var requestHeaderCallback;
+let requestHeaderCallback;
-var headerReceivedCallback;
+let headerReceivedCallback;
-var responseCallback;
+let responseCallback;
 
-var isInterceptorEnabled = false;
+let isInterceptorEnabled = false;
 
 /**
  * A network interceptor which monkey-patches XMLHttpRequest methods

Libraries/Network/XMLHttpRequest.js

@@ -421,14 +421,14 @@ class XMLHttpRequest extends EventTarget(...XHR_EVENTS) {
       // according to the spec, return null if no response has been received
       return null;
     }
-    var headers = this.responseHeaders || {};
+    const headers = this.responseHeaders || {};
     return Object.keys(headers).map((headerName) => {
       return headerName + ': ' + headers[headerName];
     }).join('\r\n');
   }
 
   getResponseHeader(header: string): ?string {
-    var value = this._lowerCaseResponseHeaders[header.toLowerCase()];
+    const value = this._lowerCaseResponseHeaders[header.toLowerCase()];
     return value !== undefined ? value : null;
   }
 
@@ -545,7 +545,7 @@ class XMLHttpRequest extends EventTarget(...XHR_EVENTS) {
 
   setResponseHeaders(responseHeaders: ?Object): void {
     this.responseHeaders = responseHeaders || null;
-    var headers = responseHeaders || {};
+    const headers = responseHeaders || {};
     this._lowerCaseResponseHeaders =
       Object.keys(headers).reduce((lcaseHeaders, headerName) => {
         lcaseHeaders[headerName.toLowerCase()] = headers[headerName];

Libraries/PushNotificationIOS/PushNotificationIOS.js

@@ -182,7 +182,7 @@ class PushNotificationIOS {
       type === 'notification' || type === 'register' || type === 'registrationError' || type === 'localNotification',
       'PushNotificationIOS only supports `notification`, `register`, `registrationError`, and `localNotification` events'
     );
-    var listener;
+    let listener;
     if (type === 'notification') {
       listener =  PushNotificationEmitter.addListener(
         DEVICE_NOTIF_EVENT,
@@ -226,7 +226,7 @@ class PushNotificationIOS {
       type === 'notification' || type === 'register' || type === 'registrationError' || type === 'localNotification',
       'PushNotificationIOS only supports `notification`, `register`, `registrationError`, and `localNotification` events'
     );
-    var listener = _notifHandlers.get(type);
+    const listener = _notifHandlers.get(type);
     if (!listener) {
       return;
     }
@@ -251,7 +251,7 @@ class PushNotificationIOS {
     badge: boolean,
     sound: boolean
   }> {
-    var requestedPermissions = {};
+    let requestedPermissions = {};
     if (permissions) {
       requestedPermissions = {
         alert: !!permissions.alert,
@@ -321,7 +321,7 @@ class PushNotificationIOS {
       // Extract data from Apple's `aps` dict as defined:
       // https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/ApplePushService.html
       Object.keys(nativeNotif).forEach((notifKey) => {
-        var notifVal = nativeNotif[notifKey];
+        const notifVal = nativeNotif[notifKey];
         if (notifKey === 'aps') {
           this._alert = notifVal.alert;
           this._sound = notifVal.sound;

Libraries/RCTTest/SnapshotViewIOS.ios.js

@@ -8,16 +8,16 @@
  */
 'use strict';
 
-var React = require('React');
+const React = require('React');
 const PropTypes = require('prop-types');
-var StyleSheet = require('StyleSheet');
+const StyleSheet = require('StyleSheet');
-var { TestModule } = require('NativeModules');
+const { TestModule } = require('NativeModules');
-var UIManager = require('UIManager');
+const UIManager = require('UIManager');
-var View = require('View');
+const View = require('View');
 
 const ViewPropTypes = require('ViewPropTypes');
 
-var requireNativeComponent = require('requireNativeComponent');
+const requireNativeComponent = require('requireNativeComponent');
 
 class SnapshotViewIOS extends React.Component<{
   onSnapshotReady?: Function,
@@ -37,8 +37,8 @@ class SnapshotViewIOS extends React.Component<{
   };
 
   render() {
-    var testIdentifier = this.props.testIdentifier || 'test';
+    const testIdentifier = this.props.testIdentifier || 'test';
-    var onSnapshotReady = this.props.onSnapshotReady || this.onDefaultAction;
+    const onSnapshotReady = this.props.onSnapshotReady || this.onDefaultAction;
     return (
       <RCTSnapshot
         style={style.snapshot}
@@ -50,7 +50,7 @@ class SnapshotViewIOS extends React.Component<{
   }
 }
 
-var style = StyleSheet.create({
+const style = StyleSheet.create({
   snapshot: {
     flex: 1,
   },
@@ -59,7 +59,7 @@ var style = StyleSheet.create({
 // Verify that RCTSnapshot is part of the UIManager since it is only loaded
 // if you have linked against RCTTest like in tests, otherwise we will have
 // a warning printed out
-var RCTSnapshot = UIManager.RCTSnapshot ?
+const RCTSnapshot = UIManager.RCTSnapshot ?
   requireNativeComponent('RCTSnapshot', SnapshotViewIOS) :
   View;
 

Libraries/ReactNative/UIManagerStatTracker.js

@@ -9,17 +9,17 @@
  */
 'use strict';
 
-var UIManager = require('UIManager');
+const UIManager = require('UIManager');
 
-var installed = false;
+let installed = false;
-var UIManagerStatTracker = {
+const UIManagerStatTracker = {
   install: function() {
     if (installed) {
       return;
     }
     installed = true;
-    var statLogHandle;
+    let statLogHandle;
-    var stats = {};
+    const stats = {};
     function printStats() {
       console.log({UIManagerStatTracker: stats});
       statLogHandle = null;
@@ -30,19 +30,19 @@ var UIManagerStatTracker = {
         statLogHandle = setImmediate(printStats);
       }
     }
-    var createViewOrig = UIManager.createView;
+    const createViewOrig = UIManager.createView;
     UIManager.createView = function(tag, className, rootTag, props) {
       incStat('createView', 1);
       incStat('setProp', Object.keys(props || []).length);
       createViewOrig(tag, className, rootTag, props);
     };
-    var updateViewOrig = UIManager.updateView;
+    const updateViewOrig = UIManager.updateView;
     UIManager.updateView = function(tag, className, props) {
       incStat('updateView', 1);
       incStat('setProp', Object.keys(props || []).length);
       updateViewOrig(tag, className, props);
     };
-    var manageChildrenOrig = UIManager.manageChildren;
+    const manageChildrenOrig = UIManager.manageChildren;
     UIManager.manageChildren = function(
       tag,
       moveFrom,

Libraries/ReactNative/YellowBox.js

@@ -452,7 +452,7 @@ const rowHeight = 46;
 const elevation =
   Platform.OS === 'android' ? Number.MAX_SAFE_INTEGER : undefined;
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   fullScreen: {
     height: '100%',
     width: '100%',

Libraries/ReactNative/queryLayoutByID.js

@@ -9,7 +9,7 @@
  */
 'use strict';
 
-var UIManager = require('UIManager');
+const UIManager = require('UIManager');
 
 type OnSuccessCallback = (
   left: number,
@@ -42,7 +42,7 @@ type OnErrorCallback = (error: any) => void;
  * @param {function} onError `func(error)`
  * @param {function} onSuccess `func(left, top, width, height, pageX, pageY)`
  */
-var queryLayoutByID = function(
+const queryLayoutByID = function(
   tag: ?number,
   onError: OnErrorCallback,
   onSuccess: OnSuccessCallback,

Libraries/Sample/Sample.android.js

@@ -5,9 +5,9 @@
  */
 'use strict';
 
-var warning = require('fbjs/lib/warning');
+const warning = require('fbjs/lib/warning');
 
-var Sample = {
+const Sample = {
   test: function() {
     warning('Not yet implemented for Android.');
   }

Libraries/Sample/Sample.ios.js

@@ -3,13 +3,13 @@
  */
 'use strict';
 
-var NativeSample = require('NativeModules').Sample;
+const NativeSample = require('NativeModules').Sample;
 
 /**
  * High-level docs for the Sample iOS API can be written here.
  */
 
-var Sample = {
+const Sample = {
   test: function() {
     NativeSample.test();
   }

Libraries/Settings/Settings.android.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var Settings = {
+const Settings = {
   get(key: string): mixed {
     console.warn('Settings is not yet supported on Android');
     return null;

Libraries/Settings/Settings.ios.js

@@ -8,14 +8,14 @@
  */
 'use strict';
 
-var RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
+const RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
-var RCTSettingsManager = require('NativeModules').SettingsManager;
+const RCTSettingsManager = require('NativeModules').SettingsManager;
 
-var invariant = require('fbjs/lib/invariant');
+const invariant = require('fbjs/lib/invariant');
 
-var subscriptions: Array<{keys: Array<string>, callback: ?Function}> = [];
+const subscriptions: Array<{keys: Array<string>, callback: ?Function}> = [];
 
-var Settings = {
+const Settings = {
   _settings: RCTSettingsManager && RCTSettingsManager.settings,
 
   get(key: string): mixed {
@@ -37,7 +37,7 @@ var Settings = {
       'keys should be a string or array of strings'
     );
 
-    var sid = subscriptions.length;
+    const sid = subscriptions.length;
     subscriptions.push({keys: keys, callback: callback});
     return sid;
   },
@@ -50,8 +50,8 @@ var Settings = {
 
   _sendObservations(body: Object) {
     Object.keys(body).forEach((key) => {
-      var newValue = body[key];
+      const newValue = body[key];
-      var didChange = this._settings[key] !== newValue;
+      const didChange = this._settings[key] !== newValue;
       this._settings[key] = newValue;
 
       if (didChange) {

Libraries/Storage/AsyncStorage.js

@@ -24,7 +24,7 @@ const RCTAsyncStorage = NativeModules.AsyncRocksDBStorage ||
  *
  * See http://facebook.github.io/react-native/docs/asyncstorage.html
  */
-var AsyncStorage = {
+const AsyncStorage = {
   _getRequests: ([]: Array<any>),
   _getKeys: ([]: Array<string>),
   _immediate: (null: ?number),
@@ -41,8 +41,8 @@ var AsyncStorage = {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiGet([key], function(errors, result) {
         // Unpack result to get value from [[key,value]]
-        var value = (result && result[0] && result[0][1]) ? result[0][1] : null;
+        const value = (result && result[0] && result[0][1]) ? result[0][1] : null;
-        var errs = convertErrors(errors);
+        const errs = convertErrors(errors);
         callback && callback(errs && errs[0], value);
         if (errs) {
           reject(errs[0]);
@@ -65,7 +65,7 @@ var AsyncStorage = {
   ): Promise {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiSet([[key,value]], function(errors) {
-        var errs = convertErrors(errors);
+        const errs = convertErrors(errors);
         callback && callback(errs && errs[0]);
         if (errs) {
           reject(errs[0]);
@@ -87,7 +87,7 @@ var AsyncStorage = {
   ): Promise {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiRemove([key], function(errors) {
-        var errs = convertErrors(errors);
+        const errs = convertErrors(errors);
         callback && callback(errs && errs[0]);
         if (errs) {
           reject(errs[0]);
@@ -113,7 +113,7 @@ var AsyncStorage = {
   ): Promise {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiMerge([[key,value]], function(errors) {
-        var errs = convertErrors(errors);
+        const errs = convertErrors(errors);
         callback && callback(errs && errs[0]);
         if (errs) {
           reject(errs[0]);
@@ -222,7 +222,7 @@ var AsyncStorage = {
       });
     }
 
-    var getRequest = {
+    const getRequest = {
       keys: keys,
       callback: callback,
       // do we need this?
@@ -231,7 +231,7 @@ var AsyncStorage = {
       reject: null,
     };
 
-    var promiseResult = new Promise((resolve, reject) => {
+    const promiseResult = new Promise((resolve, reject) => {
       getRequest.resolve = resolve;
       getRequest.reject = reject;
     });
@@ -259,7 +259,7 @@ var AsyncStorage = {
   ): Promise {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiSet(keyValuePairs, function(errors) {
-        var error = convertErrors(errors);
+        const error = convertErrors(errors);
         callback && callback(error);
         if (error) {
           reject(error);
@@ -281,7 +281,7 @@ var AsyncStorage = {
   ): Promise {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiRemove(keys, function(errors) {
-        var error = convertErrors(errors);
+        const error = convertErrors(errors);
         callback && callback(error);
         if (error) {
           reject(error);
@@ -306,7 +306,7 @@ var AsyncStorage = {
   ): Promise {
     return new Promise((resolve, reject) => {
       RCTAsyncStorage.multiMerge(keyValuePairs, function(errors) {
-        var error = convertErrors(errors);
+        const error = convertErrors(errors);
         callback && callback(error);
         if (error) {
           reject(error);
@@ -335,7 +335,7 @@ function convertError(error) {
   if (!error) {
     return null;
   }
-  var out = new Error(error.message);
+  const out = new Error(error.message);
   out.key = error.key; // flow doesn't like this :(
   return out;
 }

Libraries/StyleSheet/ColorPropType.js

@@ -7,10 +7,10 @@
  */
 'use strict';
 
-var normalizeColor = require('normalizeColor');
+const normalizeColor = require('normalizeColor');
 
-var colorPropType = function(isRequired, props, propName, componentName, location, propFullName) {
+const colorPropType = function(isRequired, props, propName, componentName, location, propFullName) {
-  var color = props[propName];
+  const color = props[propName];
   if (color === undefined || color === null) {
     if (isRequired) {
       return new Error(
@@ -48,7 +48,7 @@ var colorPropType = function(isRequired, props, propName, componentName, locatio
   }
 };
 
-var ColorPropType = colorPropType.bind(null, false /* isRequired */);
+const ColorPropType = colorPropType.bind(null, false /* isRequired */);
 ColorPropType.isRequired = colorPropType.bind(null, true /* isRequired */);
 
 module.exports = ColorPropType;

Libraries/StyleSheet/LayoutPropTypes.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var ReactPropTypes = require('prop-types');
+const ReactPropTypes = require('prop-types');
 
 /**
  * React Native's layout system is based on Flexbox and is powered both
@@ -23,7 +23,7 @@ var ReactPropTypes = require('prop-types');
  * These properties are a subset of our styles that are consumed by the layout
  * algorithm and affect the positioning and sizing of views.
  */
-var LayoutPropTypes = {
+const LayoutPropTypes = {
   /** `display` sets the display type of this component.
    *
    *  It works similarly to `display` in CSS, but only support 'flex' and 'none'.

Libraries/StyleSheet/PointPropType.js

@@ -8,11 +8,11 @@
  */
 'use strict';
 
-var PropTypes = require('prop-types');
+const PropTypes = require('prop-types');
 
-var createStrictShapeTypeChecker = require('createStrictShapeTypeChecker');
+const createStrictShapeTypeChecker = require('createStrictShapeTypeChecker');
 
-var PointPropType = createStrictShapeTypeChecker({
+const PointPropType = createStrictShapeTypeChecker({
   x: PropTypes.number,
   y: PropTypes.number,
 });

Libraries/StyleSheet/StyleSheetPropType.js

@@ -8,15 +8,15 @@
  */
 'use strict';
 
-var createStrictShapeTypeChecker = require('createStrictShapeTypeChecker');
+const createStrictShapeTypeChecker = require('createStrictShapeTypeChecker');
-var flattenStyle = require('flattenStyle');
+const flattenStyle = require('flattenStyle');
 
 function StyleSheetPropType(
   shape: {[key: string]: ReactPropsCheckType}
 ): ReactPropsCheckType {
-  var shapePropType = createStrictShapeTypeChecker(shape);
+  const shapePropType = createStrictShapeTypeChecker(shape);
   return function(props, propName, componentName, location?, ...rest) {
-    var newProps = props;
+    let newProps = props;
     if (props[propName]) {
       // Just make a dummy prop object with only the flattened style
       newProps = {};

Libraries/StyleSheet/StyleSheetValidation.js

@@ -8,11 +8,11 @@
  */
 'use strict';
 
-var ImageStylePropTypes = require('ImageStylePropTypes');
+const ImageStylePropTypes = require('ImageStylePropTypes');
-var TextStylePropTypes = require('TextStylePropTypes');
+const TextStylePropTypes = require('TextStylePropTypes');
-var ViewStylePropTypes = require('ViewStylePropTypes');
+const ViewStylePropTypes = require('ViewStylePropTypes');
 
-var invariant = require('fbjs/lib/invariant');
+const invariant = require('fbjs/lib/invariant');
 
 // Hardcoded because this is a legit case but we don't want to load it from
 // a private API. We might likely want to unify style sheet creation with how it
@@ -26,12 +26,12 @@ class StyleSheetValidation {
       return;
     }
     if (allStylePropTypes[prop] === undefined) {
-      var message1 = '"' + prop + '" is not a valid style property.';
+      const message1 = '"' + prop + '" is not a valid style property.';
-      var message2 = '\nValid style props: ' +
+      const message2 = '\nValid style props: ' +
         JSON.stringify(Object.keys(allStylePropTypes).sort(), null, '  ');
       styleError(message1, style, caller, message2);
     }
-    var error = allStylePropTypes[prop](
+    const error = allStylePropTypes[prop](
       style,
       prop,
       caller,
@@ -48,19 +48,19 @@ class StyleSheetValidation {
     if (!__DEV__) {
       return;
     }
-    for (var prop in styles[name]) {
+    for (const prop in styles[name]) {
       StyleSheetValidation.validateStyleProp(prop, styles[name], 'StyleSheet ' + name);
     }
   }
 
   static addValidStylePropTypes(stylePropTypes) {
-    for (var key in stylePropTypes) {
+    for (const key in stylePropTypes) {
       allStylePropTypes[key] = stylePropTypes[key];
     }
   }
 }
 
-var styleError = function(message1, style, caller?, message2?) {
+const styleError = function(message1, style, caller?, message2?) {
   invariant(
     false,
     message1 + '\n' + (caller || '<<unknown>>') + ': ' +
@@ -68,7 +68,7 @@ var styleError = function(message1, style, caller?, message2?) {
   );
 };
 
-var allStylePropTypes = {};
+const allStylePropTypes = {};
 
 StyleSheetValidation.addValidStylePropTypes(ImageStylePropTypes);
 StyleSheetValidation.addValidStylePropTypes(TextStylePropTypes);

Libraries/StyleSheet/TransformPropTypes.js

@@ -8,11 +8,11 @@
  */
 'use strict';
 
-var ReactPropTypes = require('prop-types');
+const ReactPropTypes = require('prop-types');
 
-var deprecatedPropType = require('deprecatedPropType');
+const deprecatedPropType = require('deprecatedPropType');
 
-var TransformMatrixPropType = function(
+const TransformMatrixPropType = function(
   props : Object,
   propName : string,
   componentName : string
@@ -25,7 +25,7 @@ var TransformMatrixPropType = function(
   }
 };
 
-var DecomposedMatrixPropType = function(
+const DecomposedMatrixPropType = function(
   props : Object,
   propName : string,
   componentName : string
@@ -38,7 +38,7 @@ var DecomposedMatrixPropType = function(
   }
 };
 
-var TransformPropTypes = {
+const TransformPropTypes = {
   /**
    * `transform` accepts an array of transformation objects. Each object specifies
    * the property that will be transformed as the key, and the value to use in the

Libraries/StyleSheet/__tests__/flattenStyle-test.js

@@ -83,8 +83,8 @@ describe('flattenStyle', () => {
 
   it('should not allocate an object when there is a single class', () => {
     const fixture = getFixture();
-    var singleStyle = flattenStyle(fixture.elementA);
+    const singleStyle = flattenStyle(fixture.elementA);
-    var singleStyleAgain = flattenStyle(fixture.elementA);
+    const singleStyleAgain = flattenStyle(fixture.elementA);
 
     expect(singleStyle).toBe(singleStyleAgain);
     expect(singleStyle).toEqual({
@@ -95,8 +95,8 @@ describe('flattenStyle', () => {
 
   it('should merge single class and style properly', () => {
     const fixture = getFixture();
-    var style = {styleA: 'overrideA', styleC: 'overrideC'};
+    const style = {styleA: 'overrideA', styleC: 'overrideC'};
-    var arrayStyle = flattenStyle([fixture.elementA, style]);
+    const arrayStyle = flattenStyle([fixture.elementA, style]);
 
     expect(arrayStyle).toEqual({
       styleA: 'overrideA',
@@ -107,8 +107,8 @@ describe('flattenStyle', () => {
 
   it('should merge multiple classes', () => {
     const fixture = getFixture();
-    var AthenB = flattenStyle([fixture.elementA, fixture.elementB]);
+    const AthenB = flattenStyle([fixture.elementA, fixture.elementB]);
-    var BthenA = flattenStyle([fixture.elementB, fixture.elementA]);
+    const BthenA = flattenStyle([fixture.elementB, fixture.elementA]);
 
     expect(AthenB).toEqual({
       styleA: 'moduleA/elementA/styleA',
@@ -122,9 +122,9 @@ describe('flattenStyle', () => {
 
   it('should merge multiple classes with style', () => {
     const fixture = getFixture();
-    var style = {styleA: 'overrideA'};
+    const style = {styleA: 'overrideA'};
-    var AthenB = flattenStyle([fixture.elementA, fixture.elementB, style]);
+    const AthenB = flattenStyle([fixture.elementA, fixture.elementB, style]);
-    var BthenA = flattenStyle([fixture.elementB, fixture.elementA, style]);
+    const BthenA = flattenStyle([fixture.elementB, fixture.elementA, style]);
 
     expect(AthenB).toEqual({
       styleA: 'overrideA',
@@ -138,8 +138,8 @@ describe('flattenStyle', () => {
 
   it('should flatten recursively', () => {
     const fixture = getFixture();
-    var style = [{styleA: 'newA', styleB: 'newB'}, {styleA: 'newA2'}];
+    const style = [{styleA: 'newA', styleB: 'newB'}, {styleA: 'newA2'}];
-    var AthenB = flattenStyle([fixture.elementA, fixture.elementB, style]);
+    const AthenB = flattenStyle([fixture.elementA, fixture.elementB, style]);
 
     expect(AthenB).toEqual({
       styleA: 'newA2',
@@ -148,7 +148,7 @@ describe('flattenStyle', () => {
   });
 
   it('should ignore invalid class names', () => {
-    var invalid = flattenStyle(1234, null);
+    const invalid = flattenStyle(1234, null);
 
     expect(invalid).toEqual(undefined);
     // Invalid class name 1234 skipping ...

Libraries/StyleSheet/__tests__/normalizeColor-test.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var normalizeColor = require('normalizeColor');
+const normalizeColor = require('normalizeColor');
 
 describe('normalizeColor', function() {
   it('should accept only spec compliant colors', function() {

Libraries/StyleSheet/__tests__/processColor-test.js

@@ -20,26 +20,26 @@ describe('processColor', () => {
   describe('predefined color names', () => {
 
     it('should convert red', () => {
-      var colorFromString = processColor('red');
+      const colorFromString = processColor('red');
-      var expectedInt = 0xFFFF0000;
+      const expectedInt = 0xFFFF0000;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
 
     it('should convert white', () => {
-      var colorFromString = processColor('white');
+      const colorFromString = processColor('white');
-      var expectedInt = 0xFFFFFFFF;
+      const expectedInt = 0xFFFFFFFF;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
 
     it('should convert black', () => {
-      var colorFromString = processColor('black');
+      const colorFromString = processColor('black');
-      var expectedInt = 0xFF000000;
+      const expectedInt = 0xFF000000;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
 
     it('should convert transparent', () => {
-      var colorFromString = processColor('transparent');
+      const colorFromString = processColor('transparent');
-      var expectedInt = 0x00000000;
+      const expectedInt = 0x00000000;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
   });
@@ -47,8 +47,8 @@ describe('processColor', () => {
   describe('RGB strings', () => {
 
     it('should convert rgb(x, y, z)', () => {
-      var colorFromString = processColor('rgb(10, 20, 30)');
+      const colorFromString = processColor('rgb(10, 20, 30)');
-      var expectedInt = 0xFF0A141E;
+      const expectedInt = 0xFF0A141E;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
 
@@ -57,8 +57,8 @@ describe('processColor', () => {
   describe('RGBA strings', () => {
 
     it('should convert rgba(x, y, z, a)', () => {
-      var colorFromString = processColor('rgba(10, 20, 30, 0.4)');
+      const colorFromString = processColor('rgba(10, 20, 30, 0.4)');
-      var expectedInt = 0x660A141E;
+      const expectedInt = 0x660A141E;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
 
@@ -67,8 +67,8 @@ describe('processColor', () => {
   describe('HSL strings', () => {
 
     it('should convert hsl(x, y%, z%)', () => {
-      var colorFromString = processColor('hsl(318, 69%, 55%)');
+      const colorFromString = processColor('hsl(318, 69%, 55%)');
-      var expectedInt = 0xFFDB3DAC;
+      const expectedInt = 0xFFDB3DAC;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
 
@@ -77,8 +77,8 @@ describe('processColor', () => {
   describe('HSLA strings', () => {
 
     it('should convert hsla(x, y%, z%, a)', () => {
-      var colorFromString = processColor('hsla(318, 69%, 55%, 0.25)');
+      const colorFromString = processColor('hsla(318, 69%, 55%, 0.25)');
-      var expectedInt = 0x40DB3DAC;
+      const expectedInt = 0x40DB3DAC;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
 
@@ -87,8 +87,8 @@ describe('processColor', () => {
   describe('hex strings', () => {
 
     it('should convert #xxxxxx', () => {
-      var colorFromString = processColor('#1e83c9');
+      const colorFromString = processColor('#1e83c9');
-      var expectedInt = 0xFF1E83C9;
+      const expectedInt = 0xFF1E83C9;
       expect(colorFromString).toEqual(platformSpecific(expectedInt));
     });
 

Libraries/StyleSheet/__tests__/setNormalizedColorAlpha-test.js

@@ -8,8 +8,8 @@
  */
 'use strict';
 
-var setNormalizedColorAlpha = require('setNormalizedColorAlpha');
+const setNormalizedColorAlpha = require('setNormalizedColorAlpha');
-var normalizeColor = require('normalizeColor');
+const normalizeColor = require('normalizeColor');
 
 describe('setNormalizedColorAlpha', function() {
   it('should adjust the alpha of the color passed in', function() {
@@ -27,7 +27,7 @@ describe('setNormalizedColorAlpha', function() {
   });
 
   it('should return the original color when alpha is unchanged', function() {
-    var originalColor = normalizeColor('blue');
+    const originalColor = normalizeColor('blue');
     expect(setNormalizedColorAlpha(originalColor, 1)).toBe(originalColor);
   });
 });

Libraries/StyleSheet/flattenStyle.js

@@ -25,11 +25,11 @@ function flattenStyle(
     return style;
   }
 
-  var result = {};
+  const result = {};
-  for (var i = 0, styleLength = style.length; i < styleLength; ++i) {
+  for (let i = 0, styleLength = style.length; i < styleLength; ++i) {
-    var computedStyle = flattenStyle(style[i]);
+    const computedStyle = flattenStyle(style[i]);
     if (computedStyle) {
-      for (var key in computedStyle) {
+      for (const key in computedStyle) {
         result[key] = computedStyle[key];
       }
     }

Libraries/StyleSheet/processTransform.js

@@ -8,11 +8,11 @@
  */
 'use strict';
 
-var MatrixMath = require('MatrixMath');
+const MatrixMath = require('MatrixMath');
-var Platform = require('Platform');
+const Platform = require('Platform');
 
-var invariant = require('fbjs/lib/invariant');
+const invariant = require('fbjs/lib/invariant');
-var stringifySafe = require('stringifySafe');
+const stringifySafe = require('stringifySafe');
 
 /**
  * Generate a transform matrix based on the provided transforms, and use that
@@ -34,11 +34,11 @@ function processTransform(transform: Array<Object>): Array<Object> | Array<numbe
     return transform;
   }
 
-  var result = MatrixMath.createIdentityMatrix();
+  const result = MatrixMath.createIdentityMatrix();
 
   transform.forEach(transformation => {
-    var key = Object.keys(transformation)[0];
+    const key = Object.keys(transformation)[0];
-    var value = transformation[key];
+    const value = transformation[key];
 
     switch (key) {
       case 'matrix':
@@ -97,8 +97,8 @@ function _multiplyTransform(
   matrixMathFunction: Function,
   args: Array<number>
 ): void {
-  var matrixToApply = MatrixMath.createIdentityMatrix();
+  const matrixToApply = MatrixMath.createIdentityMatrix();
-  var argsWithIdentity = [matrixToApply].concat(args);
+  const argsWithIdentity = [matrixToApply].concat(args);
   matrixMathFunction.apply(this, argsWithIdentity);
   MatrixMath.multiplyInto(result, result, matrixToApply);
 }
@@ -108,20 +108,20 @@ function _multiplyTransform(
  * Note that validation on the string is done in `_validateTransform()`.
  */
 function _convertToRadians(value: string): number {
-  var floatValue = parseFloat(value);
+  const floatValue = parseFloat(value);
   return value.indexOf('rad') > -1 ? floatValue : floatValue * Math.PI / 180;
 }
 
 function _validateTransforms(transform: Array<Object>): void {
   transform.forEach(transformation => {
-    var keys = Object.keys(transformation);
+    const keys = Object.keys(transformation);
     invariant(
       keys.length === 1,
       'You must specify exactly one property per transform object. Passed properties: %s',
       stringifySafe(transformation),
     );
-    var key = keys[0];
+    const key = keys[0];
-    var value = transformation[key];
+    const value = transformation[key];
     _validateTransform(key, value, transformation);
   });
 }
@@ -134,7 +134,7 @@ function _validateTransform(key, value, transformation) {
     'replace <View /> by <Animated.View />.'
   );
 
-  var multivalueTransforms = [
+  const multivalueTransforms = [
     'matrix',
     'translate',
   ];

Libraries/Text/TextUpdateTest.js

@@ -8,22 +8,22 @@
  */
 'use strict';
 
-var React = require('react');
+const React = require('react');
-var createReactClass = require('create-react-class');
+const createReactClass = require('create-react-class');
-var ReactNative = require('react-native');
+const ReactNative = require('react-native');
 /* $FlowFixMe(>=0.54.0 site=react_native_oss) This comment suppresses an error
  * found when Flow v0.54 was deployed. To see the error delete this comment and
  * run Flow. */
-var TimerMixin = require('react-timer-mixin');
+const TimerMixin = require('react-timer-mixin');
-var {
+const {
   NativeModules,
   StyleSheet,
   Text,
 } = ReactNative;
 
-var TestManager = NativeModules.TestManager || NativeModules.SnapshotTestManager;
+const TestManager = NativeModules.TestManager || NativeModules.SnapshotTestManager;
 
-var TextUpdateTest = createReactClass({
+const TextUpdateTest = createReactClass({
   displayName: 'TextUpdateTest',
   mixins: [TimerMixin],
   getInitialState: function() {
@@ -48,7 +48,7 @@ var TextUpdateTest = createReactClass({
   },
 });
 
-var styles = StyleSheet.create({
+const styles = StyleSheet.create({
   container: {
     margin: 10,
     marginTop: 100,

Libraries/Utilities/BackAndroid.js

@@ -11,14 +11,14 @@
 
 'use strict';
 
-var BackHandler = require('BackHandler');
+const BackHandler = require('BackHandler');
 
-var warning = require('fbjs/lib/warning');
+const warning = require('fbjs/lib/warning');
 
 /**
  * Deprecated.  Use BackHandler instead.
  */
-var BackAndroid = {
+const BackAndroid = {
 
   exitApp: function() {
     warning(false, 'BackAndroid is deprecated.  Please use BackHandler instead.');

Libraries/Utilities/BackHandler.android.js

@@ -8,22 +8,22 @@
 
 'use strict';
 
-var DeviceEventManager = require('NativeModules').DeviceEventManager;
+const DeviceEventManager = require('NativeModules').DeviceEventManager;
-var RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
+const RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
 
-var DEVICE_BACK_EVENT = 'hardwareBackPress';
+const DEVICE_BACK_EVENT = 'hardwareBackPress';
 
 type BackPressEventName = $Enum<{
   backPress: string,
 }>;
 
-var _backPressSubscriptions = new Set();
+const _backPressSubscriptions = new Set();
 
 RCTDeviceEventEmitter.addListener(DEVICE_BACK_EVENT, function() {
-  var invokeDefault = true;
+  let invokeDefault = true;
-  var subscriptions = Array.from(_backPressSubscriptions.values()).reverse();
+  const subscriptions = Array.from(_backPressSubscriptions.values()).reverse();
 
-  for (var i = 0; i < subscriptions.length; ++i) {
+  for (let i = 0; i < subscriptions.length; ++i) {
     if (subscriptions[i]()) {
       invokeDefault = false;
       break;
@@ -65,7 +65,7 @@ RCTDeviceEventEmitter.addListener(DEVICE_BACK_EVENT, function() {
  * });
  * ```
  */
-var BackHandler = {
+const BackHandler = {
 
   exitApp: function() {
     DeviceEventManager.invokeDefaultBackPressHandler();

Libraries/Utilities/BackHandler.ios.js

@@ -54,14 +54,14 @@ let BackHandler;
 
 if (Platform.isTVOS) {
   const _tvEventHandler = new TVEventHandler();
-  var _backPressSubscriptions = new Set();
+  const _backPressSubscriptions = new Set();
 
   _tvEventHandler.enable(this, function(cmp, evt) {
     if (evt && evt.eventType === 'menu') {
-      var invokeDefault = true;
+      let invokeDefault = true;
-      var subscriptions = Array.from(_backPressSubscriptions.values()).reverse();
+      const subscriptions = Array.from(_backPressSubscriptions.values()).reverse();
 
-      for (var i = 0; i < subscriptions.length; ++i) {
+      for (let i = 0; i < subscriptions.length; ++i) {
         if (subscriptions[i]()) {
           invokeDefault = false;
           break;

Libraries/Utilities/Dimensions.js

@@ -8,15 +8,15 @@
  */
 'use strict';
 
-var EventEmitter = require('EventEmitter');
+const EventEmitter = require('EventEmitter');
-var Platform = require('Platform');
+const Platform = require('Platform');
-var RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
+const RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');
 
-var invariant = require('fbjs/lib/invariant');
+const invariant = require('fbjs/lib/invariant');
 
-var eventEmitter = new EventEmitter();
+const eventEmitter = new EventEmitter();
-var dimensionsInitialized = false;
+let dimensionsInitialized = false;
-var dimensions = {};
+const dimensions = {};
 class Dimensions {
   /**
    * This should only be called from native code by sending the

Libraries/Utilities/HMRLoadingView.android.js

@@ -9,7 +9,7 @@
 
 'use strict';
 
-var ToastAndroid = require('ToastAndroid');
+const ToastAndroid = require('ToastAndroid');
 
 const TOAST_SHORT_DELAY = 2000;
 

Libraries/Utilities/HeapCapture.js

@@ -8,9 +8,9 @@
  */
 'use strict';
 
-var HeapCapture = {
+const HeapCapture = {
   captureHeap: function (path: string) {
-    var error = null;
+    let error = null;
     try {
       global.nativeCaptureHeap(path);
       console.log('HeapCapture.captureHeap succeeded: ' + path);

Libraries/Utilities/MatrixMath.js

@@ -9,13 +9,13 @@
 /* eslint-disable space-infix-ops */
 'use strict';
 
-var invariant = require('fbjs/lib/invariant');
+const invariant = require('fbjs/lib/invariant');
 
 /**
  * Memory conservative (mutative) matrix math utilities. Uses "command"
  * matrices, which are reusable.
  */
-var MatrixMath = {
+const MatrixMath = {
   createIdentityMatrix: function() {
     return [
       1,0,0,0,
@@ -35,13 +35,13 @@ var MatrixMath = {
   },
 
   createOrthographic: function(left, right, bottom, top, near, far) {
-    var a = 2 / (right - left);
+    const a = 2 / (right - left);
-    var b = 2 / (top - bottom);
+    const b = 2 / (top - bottom);
-    var c = -2 / (far - near);
+    const c = -2 / (far - near);
 
-    var tx = -(right + left) / (right - left);
+    const tx = -(right + left) / (right - left);
-    var ty = -(top + bottom) / (top - bottom);
+    const ty = -(top + bottom) / (top - bottom);
-    var tz = -(far + near) / (far - near);
+    const tz = -(far + near) / (far - near);
 
     return [
         a,  0,  0,  0,
@@ -52,15 +52,15 @@ var MatrixMath = {
   },
 
   createFrustum: function(left, right, bottom, top, near, far) {
-    var r_width  = 1 / (right - left);
+    const r_width  = 1 / (right - left);
-    var r_height = 1 / (top - bottom);
+    const r_height = 1 / (top - bottom);
-    var r_depth  = 1 / (near - far);
+    const r_depth  = 1 / (near - far);
-    var x = 2 * (near * r_width);
+    const x = 2 * (near * r_width);
-    var y = 2 * (near * r_height);
+    const y = 2 * (near * r_height);
-    var A = (right + left) * r_width;
+    const A = (right + left) * r_width;
-    var B = (top + bottom) * r_height;
+    const B = (top + bottom) * r_height;
-    var C = (far + near) * r_depth;
+    const C = (far + near) * r_depth;
-    var D = 2 * (far * near * r_depth);
+    const D = 2 * (far * near * r_depth);
     return [
       x, 0, 0, 0,
       0, y, 0, 0,
@@ -76,10 +76,10 @@ var MatrixMath = {
    * @param fovInRadians - field of view in randians
    */
   createPerspective: function(fovInRadians, aspect, near, far) {
-    var h = 1 / Math.tan(fovInRadians / 2);
+    const h = 1 / Math.tan(fovInRadians / 2);
-    var r_depth  = 1 / (near - far);
+    const r_depth  = 1 / (near - far);
-    var C = (far + near) * r_depth;
+    const C = (far + near) * r_depth;
-    var D = 2 * (far * near * r_depth);
+    const D = 2 * (far * near * r_depth);
     return [
       h/aspect, 0, 0, 0,
       0, h, 0, 0,
@@ -89,7 +89,7 @@ var MatrixMath = {
   },
 
   createTranslate2d: function(x, y) {
-    var mat = MatrixMath.createIdentityMatrix();
+    const mat = MatrixMath.createIdentityMatrix();
     MatrixMath.reuseTranslate2dCommand(mat, x, y);
     return mat;
   },
@@ -106,7 +106,7 @@ var MatrixMath = {
   },
 
   createScale: function(factor) {
-    var mat = MatrixMath.createIdentityMatrix();
+    const mat = MatrixMath.createIdentityMatrix();
     MatrixMath.reuseScaleCommand(mat, factor);
     return mat;
   },
@@ -161,7 +161,7 @@ var MatrixMath = {
   },
 
   createRotateZ: function(radians) {
-    var mat = MatrixMath.createIdentityMatrix();
+    const mat = MatrixMath.createIdentityMatrix();
     MatrixMath.reuseRotateZCommand(mat, radians);
     return mat;
   },
@@ -175,12 +175,9 @@ var MatrixMath = {
   },
 
   multiplyInto: function(out, a, b) {
-    var a00 = a[0], a01 = a[1], a02 = a[2], a03 = a[3],
+    const a00 = a[0], a01 = a[1], a02 = a[2], a03 = a[3], a10 = a[4], a11 = a[5], a12 = a[6], a13 = a[7], a20 = a[8], a21 = a[9], a22 = a[10], a23 = a[11], a30 = a[12], a31 = a[13], a32 = a[14], a33 = a[15];
-      a10 = a[4], a11 = a[5], a12 = a[6], a13 = a[7],
-      a20 = a[8], a21 = a[9], a22 = a[10], a23 = a[11],
-      a30 = a[12], a31 = a[13], a32 = a[14], a33 = a[15];
 
-    var b0  = b[0], b1 = b[1], b2 = b[2], b3 = b[3];
+    let b0  = b[0], b1 = b[1], b2 = b[2], b3 = b[3];
     out[0] = b0*a00 + b1*a10 + b2*a20 + b3*a30;
     out[1] = b0*a01 + b1*a11 + b2*a21 + b3*a31;
     out[2] = b0*a02 + b1*a12 + b2*a22 + b3*a32;
@@ -206,7 +203,7 @@ var MatrixMath = {
   },
 
   determinant(matrix: Array<number>): number {
-    var [
+    const [
       m00, m01, m02, m03,
       m10, m11, m12, m13,
       m20, m21, m22, m23,
@@ -236,11 +233,11 @@ var MatrixMath = {
    * http://www.euclideanspace.com/maths/algebra/matrix/functions/inverse/fourD/index.htm
    */
   inverse(matrix: Array<number>): Array<number> {
-    var det = MatrixMath.determinant(matrix);
+    const det = MatrixMath.determinant(matrix);
     if (!det) {
       return matrix;
     }
-    var [
+    const [
       m00, m01, m02, m03,
       m10, m11, m12, m13,
       m20, m21, m22, m23,
@@ -285,7 +282,7 @@ var MatrixMath = {
     v: Array<number>,
     m: Array<number>
   ): Array<number> {
-    var [vx, vy, vz, vw] = v;
+    const [vx, vy, vz, vw] = v;
     return [
       vx * m[0] + vy * m[4] + vz * m[8]  + vw * m[12],
       vx * m[1] + vy * m[5] + vz * m[9]  + vw * m[13],
@@ -308,7 +305,7 @@ var MatrixMath = {
      vector: Array<number>,
      v3Length: number
     ): Array<number> {
-    var im = 1 / (v3Length || MatrixMath.v3Length(vector));
+    const im = 1 / (v3Length || MatrixMath.v3Length(vector));
     return [
       vector[0] * im,
       vector[1] * im,
@@ -372,14 +369,14 @@ var MatrixMath = {
    * roll  === bank               === x-axis
    */
   quaternionToDegreesXYZ(q: Array<number>, matrix, row): Array<number> {
-    var [qx, qy, qz, qw] = q;
+    const [qx, qy, qz, qw] = q;
-    var qw2 = qw * qw;
+    const qw2 = qw * qw;
-    var qx2 = qx * qx;
+    const qx2 = qx * qx;
-    var qy2 = qy * qy;
+    const qy2 = qy * qy;
-    var qz2 = qz * qz;
+    const qz2 = qz * qz;
-    var test = qx * qy + qz * qw;
+    const test = qx * qy + qz * qw;
-    var unit = qw2 + qx2 + qy2 + qz2;
+    const unit = qw2 + qx2 + qy2 + qz2;
-    var conv = 180 / Math.PI;
+    const conv = 180 / Math.PI;
 
     if (test > 0.49999 * unit) {
       return [0, 2 * Math.atan2(qx, qw) * conv, 90];
@@ -406,7 +403,7 @@ var MatrixMath = {
    * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/round
    */
   roundTo3Places(n: number): number {
-    var arr = n.toString().split('e');
+    const arr = n.toString().split('e');
     return Math.round(arr[0] + 'e' + (arr[1] ? (+arr[1] - 3) : 3)) * 0.001;
   },
 
@@ -431,22 +428,22 @@ var MatrixMath = {
 
     // output values
     var perspective = [];
-    var quaternion = [];
+    const quaternion = [];
-    var scale = [];
+    const scale = [];
-    var skew = [];
+    const skew = [];
-    var translation = [];
+    const translation = [];
 
     // create normalized, 2d array matrix
     // and normalized 1d array perspectiveMatrix with redefined 4th column
     if (!transformMatrix[15]) {
       return;
     }
-    var matrix = [];
+    const matrix = [];
-    var perspectiveMatrix = [];
+    const perspectiveMatrix = [];
     for (var i = 0; i < 4; i++) {
       matrix.push([]);
-      for (var j = 0; j < 4; j++) {
+      for (let j = 0; j < 4; j++) {
-        var value = transformMatrix[(i * 4) + j] / transformMatrix[15];
+        const value = transformMatrix[(i * 4) + j] / transformMatrix[15];
         matrix[i].push(value);
         perspectiveMatrix.push(j === 3 ? 0 : value);
       }
@@ -462,7 +459,7 @@ var MatrixMath = {
     if (matrix[0][3] !== 0 || matrix[1][3] !== 0 || matrix[2][3] !== 0) {
       // rightHandSide is the right hand side of the equation.
       // rightHandSide is a vector, or point in 3d space relative to the origin.
-      var rightHandSide = [
+      const rightHandSide = [
         matrix[0][3],
         matrix[1][3],
         matrix[2][3],
@@ -471,10 +468,10 @@ var MatrixMath = {
 
       // Solve the equation by inverting perspectiveMatrix and multiplying
       // rightHandSide by the inverse.
-      var inversePerspectiveMatrix = MatrixMath.inverse(
+      const inversePerspectiveMatrix = MatrixMath.inverse(
         perspectiveMatrix
       );
-      var transposedInversePerspectiveMatrix = MatrixMath.transpose(
+      const transposedInversePerspectiveMatrix = MatrixMath.transpose(
         inversePerspectiveMatrix
       );
       var perspective = MatrixMath.multiplyVectorByMatrix(
@@ -494,7 +491,7 @@ var MatrixMath = {
 
     // Now get scale and shear.
     // 'row' is a 3 element array of 3 component vectors
-    var row = [];
+    const row = [];
     for (i = 0; i < 3; i++) {
       row[i] = [
         matrix[i][0],
@@ -535,7 +532,7 @@ var MatrixMath = {
     // At this point, the matrix (in rows) is orthonormal.
     // Check for a coordinate system flip.  If the determinant
     // is -1, then negate the matrix and the scaling factors.
-    var pdum3 = MatrixMath.v3Cross(row[1], row[2]);
+    const pdum3 = MatrixMath.v3Cross(row[1], row[2]);
     if (MatrixMath.v3Dot(row[0], pdum3) < 0) {
       for (i = 0; i < 3; i++) {
         scale[i] *= -1;
@@ -566,7 +563,7 @@ var MatrixMath = {
     }
 
     // correct for occasional, weird Euler synonyms for 2d rotation
-    var rotationDegrees;
+    let rotationDegrees;
     if (
       quaternion[0] < 0.001 && quaternion[0] >= 0 &&
       quaternion[1] < 0.001 && quaternion[1] >= 0

Libraries/Utilities/PixelRatio.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var Dimensions = require('Dimensions');
+const Dimensions = require('Dimensions');
 
 /**
  * PixelRatio class gives access to the device pixel density.
@@ -108,7 +108,7 @@ class PixelRatio {
    * exactly (8.33 * 3) = 25 pixels.
    */
   static roundToNearestPixel(layoutSize: number): number {
-    var ratio = PixelRatio.get();
+    const ratio = PixelRatio.get();
     return Math.round(layoutSize * ratio) / ratio;
   }
 

Libraries/Utilities/__tests__/MatrixMath-test.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var MatrixMath = require('MatrixMath');
+const MatrixMath = require('MatrixMath');
 
 function degreesToRadians(degrees) {
   return degrees * Math.PI / 180;
@@ -26,7 +26,7 @@ describe('MatrixMath', () => {
     ]).rotationDegrees).toEqual([0, 0, 0]);
 
     [30, 45, 60, 75, 90, 100, 115, 120, 133, 167].forEach(angle => {
-      var mat = MatrixMath.createRotateZ(degreesToRadians(angle));
+      let mat = MatrixMath.createRotateZ(degreesToRadians(angle));
       expect(convertZeroes(MatrixMath.decomposeMatrix(mat).rotationDegrees))
         .toEqual([0, 0, angle]);
 
@@ -80,7 +80,7 @@ describe('MatrixMath', () => {
   });
 
   it('decomposes a 4x4 matrix to produce accurate Y-axis angles', () => {
-    var mat;
+    let mat;
     [30, 45, 60, 75, 90, 100, 110, 120, 133, 167].forEach(angle => {
       mat = MatrixMath.createIdentityMatrix();
       MatrixMath.reuseRotateYCommand(mat, degreesToRadians(angle));
@@ -112,7 +112,7 @@ describe('MatrixMath', () => {
   });
 
   it('decomposes a 4x4 matrix to produce accurate X-axis angles', () => {
-    var mat;
+    let mat;
     [30, 45, 60, 75, 90, 100, 110, 120, 133, 167].forEach(angle => {
       mat = MatrixMath.createIdentityMatrix();
       MatrixMath.reuseRotateXCommand(mat, degreesToRadians(angle));

Libraries/Utilities/__tests__/Platform-test.js

@@ -8,8 +8,8 @@
  */
 'use strict';
 
-var PlatformIOS = require('../Platform.ios');
+const PlatformIOS = require('../Platform.ios');
-var PlatformAndroid = require('../Platform.android');
+const PlatformAndroid = require('../Platform.android');
 
 describe('Platform', () => {
 

Libraries/Utilities/__tests__/buildStyleInterpolator-test.js

@@ -8,11 +8,11 @@
  */
 'use strict';
 
-var buildStyleInterpolator = require('buildStyleInterpolator');
+const buildStyleInterpolator = require('buildStyleInterpolator');
 
-var validateEmpty = function(interpolator, value, validator) {
+const validateEmpty = function(interpolator, value, validator) {
-  var emptyObject = {};
+  const emptyObject = {};
-  var changed = interpolator(emptyObject, value);
+  let changed = interpolator(emptyObject, value);
   validator(emptyObject);
   expect(changed).toBe(true);
   changed = interpolator(emptyObject, value);
@@ -20,7 +20,7 @@ var validateEmpty = function(interpolator, value, validator) {
 };
 describe('buildStyleInterpolator', function() {
   it('should linearly interpolate without extrapolating', function() {
-    var testAnim = {
+    const testAnim = {
       opacity: {
         from: 100,
         to: 200,
@@ -42,7 +42,7 @@ describe('buildStyleInterpolator', function() {
         value: 23.5,
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
     validateEmpty(interpolator, 0, function(res) {
       expect(res).toEqual({
         opacity: 100,
@@ -80,7 +80,7 @@ describe('buildStyleInterpolator', function() {
     });
   });
   it('should linearly interpolate with extrapolating', function() {
-    var testAnim = {
+    const testAnim = {
       opacity: {
         from: 100,
         to: 200,
@@ -104,7 +104,7 @@ describe('buildStyleInterpolator', function() {
         value: 23.5,
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
     validateEmpty(interpolator, 0, function(res) {
       expect(res).toEqual({
         opacity: 100,
@@ -142,7 +142,7 @@ describe('buildStyleInterpolator', function() {
     });
   });
   it('should round accordingly', function() {
-    var testAnim = {
+    const testAnim = {
       opacity: {
         from: 0,
         to: 1,
@@ -153,7 +153,7 @@ describe('buildStyleInterpolator', function() {
         extrapolate: true,
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
     validateEmpty(interpolator, 0, function(res) {
       expect(res).toEqual({
         opacity: 0,
@@ -186,7 +186,7 @@ describe('buildStyleInterpolator', function() {
     });
   });
   it('should detect chnages correctly', function() {
-    var testAnim = {
+    const testAnim = {
       opacity: {
         from: 0,
         to: 1,
@@ -197,9 +197,9 @@ describe('buildStyleInterpolator', function() {
         extrapolate: false,
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
-    var obj = {};
+    const obj = {};
-    var res = interpolator(obj, 0);
+    let res = interpolator(obj, 0);
     expect(obj).toEqual({
       opacity: 0,
     });
@@ -227,14 +227,14 @@ describe('buildStyleInterpolator', function() {
     expect(res).toBe(false);
   });
   it('should handle identity', function() {
-    var testAnim = {
+    const testAnim = {
       opacity: {
         type: 'identity',
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
-    var obj = {};
+    const obj = {};
-    var res = interpolator(obj, 0.5);
+    let res = interpolator(obj, 0.5);
     expect(obj).toEqual({
       opacity: 0.5,
     });
@@ -248,7 +248,7 @@ describe('buildStyleInterpolator', function() {
     expect(res).toBe(false);
   });
   it('should translate', function() {
-    var testAnim = {
+    const testAnim = {
       transformTranslate: {
         from: {x: 1, y: 10, z: 100},
         to: {x: 5, y: 50, z: 500},
@@ -257,9 +257,9 @@ describe('buildStyleInterpolator', function() {
         type: 'linear',
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
-    var obj = {};
+    const obj = {};
-    var res = interpolator(obj, 1);
+    const res = interpolator(obj, 1);
     expect(obj).toEqual({
       transform: [{matrix: [1, 0, 0, 0,
                             0, 1, 0, 0,
@@ -269,7 +269,7 @@ describe('buildStyleInterpolator', function() {
     expect(res).toBe(true);
   });
   it('should scale', function() {
-    var testAnim = {
+    const testAnim = {
       transformScale: {
         from: {x: 1, y: 10, z: 100},
         to: {x: 5, y: 50, z: 500},
@@ -278,9 +278,9 @@ describe('buildStyleInterpolator', function() {
         type: 'linear',
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
-    var obj = {};
+    const obj = {};
-    var res = interpolator(obj, 1);
+    const res = interpolator(obj, 1);
     expect(obj).toEqual({
       transform: [{matrix: [2, 0, 0, 0,
                             0, 20, 0, 0,
@@ -290,7 +290,7 @@ describe('buildStyleInterpolator', function() {
     expect(res).toBe(true);
   });
   it('should combine scale and translate', function() {
-    var testAnim = {
+    const testAnim = {
       transformScale: {
         from: {x: 1, y: 10, z: 100},
         to: {x: 5, y: 50, z: 500},
@@ -306,9 +306,9 @@ describe('buildStyleInterpolator', function() {
         type: 'linear',
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
-    var obj = {};
+    const obj = {};
-    var res = interpolator(obj, 1);
+    const res = interpolator(obj, 1);
     expect(obj).toEqual({
       transform: [{matrix: [2, 0, 0, 0,
                             0, 20, 0, 0,
@@ -318,7 +318,7 @@ describe('buildStyleInterpolator', function() {
     expect(res).toBe(true);
   });
   it('should step', function() {
-    var testAnim = {
+    const testAnim = {
       opacity: {
         threshold: 13,
         from: 10,
@@ -326,9 +326,9 @@ describe('buildStyleInterpolator', function() {
         type: 'step',
       },
     };
-    var interpolator = buildStyleInterpolator(testAnim);
+    const interpolator = buildStyleInterpolator(testAnim);
-    var obj = {};
+    const obj = {};
-    var res = interpolator(obj, 0);
+    let res = interpolator(obj, 0);
     expect(obj).toEqual({
       opacity: 10,
     });

Libraries/Utilities/__tests__/deepFreezeAndThrowOnMutationInDev-test.js

@@ -6,7 +6,7 @@
  *
  * @emails oncall+react_native
  */
-var deepFreezeAndThrowOnMutationInDev = require('deepFreezeAndThrowOnMutationInDev');
+const deepFreezeAndThrowOnMutationInDev = require('deepFreezeAndThrowOnMutationInDev');
 
 describe('deepFreezeAndThrowOnMutationInDev', function() {
 
@@ -28,7 +28,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
   it('should throw on mutation in dev with strict', () => {
     'use strict';
     __DEV__ = true;
-    var o = {key: 'oldValue'};
+    const o = {key: 'oldValue'};
     deepFreezeAndThrowOnMutationInDev(o);
     expect(() => { o.key = 'newValue'; }).toThrowError(
       'You attempted to set the key `key` with the value `"newValue"` ' +
@@ -39,7 +39,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
 
   it('should throw on mutation in dev without strict', () => {
     __DEV__ = true;
-    var o = {key: 'oldValue'};
+    const o = {key: 'oldValue'};
     deepFreezeAndThrowOnMutationInDev(o);
     expect(() => { o.key = 'newValue'; }).toThrowError(
       'You attempted to set the key `key` with the value `"newValue"` ' +
@@ -51,7 +51,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
   it('should throw on nested mutation in dev with strict', () => {
     'use strict';
     __DEV__ = true;
-    var o = {key1: {key2: {key3: 'oldValue'}}};
+    const o = {key1: {key2: {key3: 'oldValue'}}};
     deepFreezeAndThrowOnMutationInDev(o);
     expect(() => { o.key1.key2.key3 = 'newValue'; }).toThrowError(
       'You attempted to set the key `key3` with the value `"newValue"` ' +
@@ -62,7 +62,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
 
   it('should throw on nested mutation in dev without strict', () => {
     __DEV__ = true;
-    var o = {key1: {key2: {key3: 'oldValue'}}};
+    const o = {key1: {key2: {key3: 'oldValue'}}};
     deepFreezeAndThrowOnMutationInDev(o);
     expect(() => { o.key1.key2.key3 = 'newValue'; }).toThrowError(
       'You attempted to set the key `key3` with the value `"newValue"` ' +
@@ -74,7 +74,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
   it('should throw on insertion in dev with strict', () => {
     'use strict';
     __DEV__ = true;
-    var o = {oldKey: 'value'};
+    const o = {oldKey: 'value'};
     deepFreezeAndThrowOnMutationInDev(o);
     expect(() => { o.newKey = 'value'; })
       .toThrowError(
@@ -85,7 +85,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
 
   it('should not throw on insertion in dev without strict', () => {
     __DEV__ = true;
-    var o = {oldKey: 'value'};
+    const o = {oldKey: 'value'};
     deepFreezeAndThrowOnMutationInDev(o);
     expect(() => { o.newKey = 'value'; }).not.toThrow();
     expect(o.newKey).toBe(undefined);
@@ -94,7 +94,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
   it('should mutate and not throw on mutation in prod', () => {
     'use strict';
     __DEV__ = false;
-    var o = {key: 'oldValue'};
+    const o = {key: 'oldValue'};
     deepFreezeAndThrowOnMutationInDev(o);
     expect(() => { o.key = 'newValue'; }).not.toThrow();
     expect(o.key).toBe('newValue');
@@ -104,7 +104,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
   it('should not deep freeze already frozen objects', () => {
     'use strict';
     __DEV__ = true;
-    var o = {key1: {key2: 'oldValue'}};
+    const o = {key1: {key2: 'oldValue'}};
     Object.freeze(o);
     deepFreezeAndThrowOnMutationInDev(o);
     expect(() => { o.key1.key2 = 'newValue'; }).not.toThrow();
@@ -113,7 +113,7 @@ describe('deepFreezeAndThrowOnMutationInDev', function() {
 
   it("shouldn't recurse infinitely", () => {
     __DEV__ = true;
-    var o = {};
+    const o = {};
     o.circular = o;
     deepFreezeAndThrowOnMutationInDev(o);
   });

Libraries/Utilities/__tests__/groupByEveryN-test.js

@@ -9,7 +9,7 @@
 'use strict';
 
 describe('groupByEveryN', () => {
-  var groupByEveryN = require('groupByEveryN');
+  const groupByEveryN = require('groupByEveryN');
 
   it('should group by with different n', () => {
     expect(groupByEveryN([1, 2, 3, 4, 5, 6, 7, 8, 9], 1))

Libraries/Utilities/__tests__/truncate-test.js

@@ -10,7 +10,7 @@
 
 describe('truncate', () => {
 
-  var truncate = require('truncate');
+  const truncate = require('truncate');
 
   it('should truncate', () => {
     expect(truncate('Hello, world.', 5))

Libraries/Utilities/buildStyleInterpolator.js

@@ -8,18 +8,18 @@
 
 'use strict';
 
-var keyOf = require('fbjs/lib/keyOf');
+const keyOf = require('fbjs/lib/keyOf');
 
-var X_DIM = keyOf({x: null});
+const X_DIM = keyOf({x: null});
-var Y_DIM = keyOf({y: null});
+const Y_DIM = keyOf({y: null});
-var Z_DIM = keyOf({z: null});
+const Z_DIM = keyOf({z: null});
 
-var InitialOperationField = {
+const InitialOperationField = {
   transformTranslate: [0, 0, 0],
   transformScale: [1, 1, 1],
 };
 
-var InterpolateMatrix = {
+const InterpolateMatrix = {
   transformScale: function(mat, x, y, z) {
     mat[0] = mat[0] * x;
     mat[1] = mat[1] * x;
@@ -42,27 +42,27 @@ var InterpolateMatrix = {
   }
 };
 
-var computeNextValLinear = function(anim, from, to, value) {
+const computeNextValLinear = function(anim, from, to, value) {
-  var hasRoundRatio = 'round' in anim;
+  const hasRoundRatio = 'round' in anim;
-  var roundRatio = anim.round;
+  const roundRatio = anim.round;
-  var ratio = (value - anim.min) / (anim.max - anim.min);
+  let ratio = (value - anim.min) / (anim.max - anim.min);
   if (!anim.extrapolate) {
     ratio = ratio > 1 ? 1 : (ratio < 0 ? 0 : ratio);
   }
-  var nextVal = from * (1 - ratio) + to * ratio;
+  let nextVal = from * (1 - ratio) + to * ratio;
   if (hasRoundRatio) {
     nextVal = Math.round(roundRatio * nextVal) / roundRatio;
   }
   return nextVal;
 };
 
-var computeNextValLinearScalar = function(anim, value) {
+const computeNextValLinearScalar = function(anim, value) {
   return computeNextValLinear(anim, anim.from, anim.to, value);
 };
 
-var setNextValAndDetectChange = function(result, name, nextVal, didChange) {
+const setNextValAndDetectChange = function(result, name, nextVal, didChange) {
   if (!didChange) {
-    var prevVal = result[name];
+    const prevVal = result[name];
     result[name] = nextVal;
     didChange = didChange  || (nextVal !== prevVal);
   } else {
@@ -71,7 +71,7 @@ var setNextValAndDetectChange = function(result, name, nextVal, didChange) {
   return didChange;
 };
 
-var initIdentity = function(mat) {
+const initIdentity = function(mat) {
   mat[0] = 1;
   mat[1] = 0;
   mat[2] = 0;
@@ -90,7 +90,7 @@ var initIdentity = function(mat) {
   mat[15] = 1;
 };
 
-var computeNextMatrixOperationField = function(anim, name, dim, index, value) {
+const computeNextMatrixOperationField = function(anim, name, dim, index, value) {
   if (anim.from[dim] !== undefined && anim.to[dim] !== undefined) {
     return computeNextValLinear(anim, anim.from[dim], anim.to[dim], value);
   } else {
@@ -98,33 +98,33 @@ var computeNextMatrixOperationField = function(anim, name, dim, index, value) {
   }
 };
 
-var computeTransform = function(anim, name, value, result,
+const computeTransform = function(anim, name, value, result,
                                 didChange, didMatrix) {
-  var transform = result.transform !== undefined ?
+  const transform = result.transform !== undefined ?
         result.transform : (result.transform = [{ matrix: [] }]);
-  var mat = transform[0].matrix;
+  const mat = transform[0].matrix;
-  var m0 = mat[0];
+  const m0 = mat[0];
-  var m1 = mat[1];
+  const m1 = mat[1];
-  var m2 = mat[2];
+  const m2 = mat[2];
-  var m3 = mat[3];
+  const m3 = mat[3];
-  var m4 = mat[4];
+  const m4 = mat[4];
-  var m5 = mat[5];
+  const m5 = mat[5];
-  var m6 = mat[6];
+  const m6 = mat[6];
-  var m7 = mat[7];
+  const m7 = mat[7];
-  var m8 = mat[8];
+  const m8 = mat[8];
-  var m9 = mat[9];
+  const m9 = mat[9];
-  var m10 = mat[10];
+  const m10 = mat[10];
-  var m11 = mat[11];
+  const m11 = mat[11];
-  var m12 = mat[12];
+  const m12 = mat[12];
-  var m13 = mat[13];
+  const m13 = mat[13];
-  var m14 = mat[14];
+  const m14 = mat[14];
-  var m15 = mat[15];
+  const m15 = mat[15];
   if (!didMatrix) {
     initIdentity(mat);  // This will be the first transform.
   }
-  var x = computeNextMatrixOperationField(anim, name, X_DIM, 0, value);
+  const x = computeNextMatrixOperationField(anim, name, X_DIM, 0, value);
-  var y = computeNextMatrixOperationField(anim, name, Y_DIM, 1, value);
+  const y = computeNextMatrixOperationField(anim, name, Y_DIM, 1, value);
-  var z = computeNextMatrixOperationField(anim, name, Z_DIM, 2, value);
+  const z = computeNextMatrixOperationField(anim, name, Z_DIM, 2, value);
   InterpolateMatrix[name](mat, x, y, z);
   if (!didChange) {
     didChange = m0 !== mat[0] || m1 !== mat[1] ||
@@ -144,12 +144,12 @@ var computeTransform = function(anim, name, value, result,
  * @return {function} Function accepting style object, that mutates that style
  * object and returns a boolean describing if any update was actually applied.
  */
-var buildStyleInterpolator = function(anims) {
+const buildStyleInterpolator = function(anims) {
   function styleInterpolator(result, value) {
-    var didChange = false;
+    let didChange = false;
-    var didMatrix = false;
+    let didMatrix = false;
-    for (var name in anims) {
+    for (const name in anims) {
-      var anim = anims[name];
+      const anim = anims[name];
       if (anim.type === 'linear') {
         if (name in InterpolateMatrix) {
           didChange = computeTransform(anim, name, value, result,

Libraries/Utilities/createStrictShapeTypeChecker.js

@@ -8,8 +8,8 @@
  */
 'use strict';
 
-var invariant = require('fbjs/lib/invariant');
+const invariant = require('fbjs/lib/invariant');
-var merge = require('merge');
+const merge = require('merge');
 
 function createStrictShapeTypeChecker(
   shapeTypes: {[key: string]: ReactPropsCheckType}
@@ -25,9 +25,9 @@ function createStrictShapeTypeChecker(
       }
       return;
     }
-    var propValue = props[propName];
+    const propValue = props[propName];
-    var propType = typeof propValue;
+    const propType = typeof propValue;
-    var locationName = location || '(unknown)';
+    const locationName = location || '(unknown)';
     if (propType !== 'object') {
       invariant(
         false,
@@ -37,9 +37,9 @@ function createStrictShapeTypeChecker(
     }
     // We need to check all keys in case some are required but missing from
     // props.
-    var allKeys = merge(props[propName], shapeTypes);
+    const allKeys = merge(props[propName], shapeTypes);
-    for (var key in allKeys) {
+    for (const key in allKeys) {
-      var checker = shapeTypes[key];
+      const checker = shapeTypes[key];
       if (!checker) {
         invariant(
           false,
@@ -48,7 +48,7 @@ function createStrictShapeTypeChecker(
             '\nValid keys: ' + JSON.stringify(Object.keys(shapeTypes), null, '  ')
         );
       }
-      var error = checker(propValue, key, componentName, location, ...rest);
+      const error = checker(propValue, key, componentName, location, ...rest);
       if (error) {
         invariant(
           false,

Libraries/Utilities/deepFreezeAndThrowOnMutationInDev.js

@@ -35,7 +35,7 @@ function deepFreezeAndThrowOnMutationInDev<T: Object>(object: T): T {
       return object;
     }
 
-    var keys = Object.keys(object);
+    const keys = Object.keys(object);
 
     for (var i = 0; i < keys.length; i++) {
       var key = keys[i];

Libraries/Utilities/differ/__tests__/deepDiffer-test.js

@@ -8,7 +8,7 @@
  */
 'use strict';
 
-var deepDiffer = require('deepDiffer');
+const deepDiffer = require('deepDiffer');
 
 describe('deepDiffer', function() {
   it('should diff primitives of the same type', () => {
@@ -95,7 +95,7 @@ describe('deepDiffer', function() {
     expect(deepDiffer(['a', 'b'], {length: 2, 0: 'a', 1: 'b'})).toBe(true);
   });
   it('should diff same object', () => {
-    var obj = [1,[2,3]];
+    const obj = [1,[2,3]];
     expect(deepDiffer(obj, obj)).toBe(false);
   });
   it('should respect maxDepth arg', () => {

Libraries/Utilities/differ/deepDiffer.js

@@ -11,7 +11,7 @@
 /*
  * @returns {bool} true if different, false if equal
  */
-var deepDiffer = function(one: any, two: any, maxDepth: number = -1): bool {
+const deepDiffer = function(one: any, two: any, maxDepth: number = -1): bool {
   if (maxDepth === 0) {
     return true;
   }
@@ -37,22 +37,22 @@ var deepDiffer = function(one: any, two: any, maxDepth: number = -1): bool {
   }
   if (Array.isArray(one)) {
     // We know two is also an array because the constructors are equal
-    var len = one.length;
+    const len = one.length;
     if (two.length !== len) {
       return true;
     }
-    for (var ii = 0; ii < len; ii++) {
+    for (let ii = 0; ii < len; ii++) {
       if (deepDiffer(one[ii], two[ii], maxDepth - 1)) {
         return true;
       }
     }
   } else {
-    for (var key in one) {
+    for (const key in one) {
       if (deepDiffer(one[key], two[key], maxDepth - 1)) {
         return true;
       }
     }
-    for (var twoKey in two) {
+    for (const twoKey in two) {
       // The only case we haven't checked yet is keys that are in two but aren't
       // in one, which means they are different.
       if (one[twoKey] === undefined && two[twoKey] !== undefined) {

Libraries/Utilities/differ/insetsDiffer.js

@@ -15,14 +15,14 @@ type Inset = {
   bottom: ?number,
 }
 
-var dummyInsets = {
+const dummyInsets = {
 	top: undefined,
 	left: undefined,
 	right: undefined,
 	bottom: undefined,
 };
 
-var insetsDiffer = function(
+const insetsDiffer = function(
   one: ?Inset,
   two: ?Inset
 ): bool {

Libraries/Utilities/differ/matricesDiffer.js

@@ -16,7 +16,7 @@
  * @param {MatrixMath.Matrix} two Second matrix.
  * @return {boolean} Whether or not the two matrices differ.
  */
-var matricesDiffer = function(one, two) {
+const matricesDiffer = function(one, two) {
   if (one === two) {
     return false;
   }

Libraries/Utilities/differ/pointsDiffer.js

@@ -13,9 +13,9 @@ type Point = {
   y: ?number,
 }
 
-var dummyPoint = {x: undefined, y: undefined};
+const dummyPoint = {x: undefined, y: undefined};
 
-var pointsDiffer = function(one: ?Point, two: ?Point): bool {
+const pointsDiffer = function(one: ?Point, two: ?Point): bool {
   one = one || dummyPoint;
   two = two || dummyPoint;
   return one !== two && (

Libraries/Utilities/differ/sizesDiffer.js

@@ -7,9 +7,9 @@
  */
 'use strict';
 
-var dummySize = {width: undefined, height: undefined};
+const dummySize = {width: undefined, height: undefined};
 
-var sizesDiffer = function(one, two) {
+const sizesDiffer = function(one, two) {
   one = one || dummySize;
   two = two || dummySize;
   return one !== two && (

Libraries/Utilities/dismissKeyboard.js

@@ -9,7 +9,7 @@
  */
 'use strict';
 
-var TextInputState = require('TextInputState');
+const TextInputState = require('TextInputState');
 
 function dismissKeyboard() {
   TextInputState.blurTextInput(TextInputState.currentlyFocusedField());

Libraries/Utilities/groupByEveryN.js

@@ -25,10 +25,10 @@
 'use strict';
 
 function groupByEveryN<T>(array: Array<T>, n: number): Array<Array<?T>> {
-  var result = [];
+  const result = [];
-  var temp = [];
+  let temp = [];
 
-  for (var i = 0; i < array.length; ++i) {
+  for (let i = 0; i < array.length; ++i) {
     if (i > 0 && i % n === 0) {
       result.push(temp);
       temp = [];

Libraries/Utilities/logError.js

@@ -13,9 +13,9 @@
  * `console.error` as a failure callback - it's not properly bound.  If passes an
  * `Error` object, it will print the message and stack.
  */
-var logError = function(...args: $ReadOnlyArray<mixed>) {
+const logError = function(...args: $ReadOnlyArray<mixed>) {
   if (args.length === 1 && args[0] instanceof Error) {
-    var err = args[0];
+    const err = args[0];
     console.error('Error: "' + err.message + '".  Stack:\n' + err.stack);
   } else {
     console.error.apply(console, args);

Libraries/Utilities/mergeIntoFast.js

@@ -15,8 +15,8 @@
  * @param {object} one Object to assign to.
  * @param {object} two Object to assign from.
  */
-var mergeIntoFast = function(one: Object, two: Object): void {
+const mergeIntoFast = function(one: Object, two: Object): void {
-  for (var keyTwo in two) {
+  for (const keyTwo in two) {
     one[keyTwo] = two[keyTwo];
   }
 };