change `isPolyfill` to `type = 'module' | 'script'`

Summary: When building, we will process modules in a special way, *not* polyfillys. We will also add more types of (virtual) files that are not modules. That’s why a “type” property makes more sense.

Reviewed By: cpojer

Differential Revision: D4244583

fbshipit-source-id: 92a0b4a0a2026d0b97ba88034483a6ce4e0c1ebb

packager/react-packager/src/ModuleGraph/Graph.js

@@ -50,7 +50,7 @@ type LoadQueue =
   Async$Queue<{id: string, parent: string}, Callback<File, Array<string>>>;
 
 const createParentModule =
-  () => ({file: {code: '', isPolyfill: false, path: ''}, dependencies: []});
+  () => ({file: {code: '', type: 'script', path: ''}, dependencies: []});
 
 const noop = () => {};
 const NO_OPTIONS = {};

packager/react-packager/src/ModuleGraph/types.flow.js

@@ -40,11 +40,13 @@ type Dependency = {|
 
 export type File = {|
   code: string,
-  isPolyfill: boolean,
   map?: ?Object,
   path: string,
+  type: FileTypes,
 |};
 
+type FileTypes = 'module' | 'script';
+
 export type Module = {|
   dependencies: Array<Dependency>,
   file: File,
@@ -82,9 +84,9 @@ export type TransformedFile = {
   code: string,
   file: string,
   hasteID: ?string,
-  isPolyfill: boolean,
   package?: PackageData,
   transformed: {[variant: string]: TransformResult},
+  type: FileTypes,
 };
 
 export type PackageData = {|

packager/react-packager/src/ModuleGraph/worker/__tests__/transform-module-test.js

@@ -62,16 +62,16 @@ describe('transforming JS modules:', () => {
     });
   });
 
-  it('sets `isPolyfill` to `false` by default', done => {
+  it('sets `type` to `"module"` by default', done => {
     transformModule(sourceCode, options(), (error, result) => {
-      expect(result).toEqual(objectContaining({isPolyfill: false}));
+      expect(result).toEqual(objectContaining({type: 'module'}));
       done();
     });
   });
 
-  it('sets `isPolyfill` to `true` if the input is a polyfill', done => {
+  it('sets `type` to `"script"` if the input is a polyfill', done => {
     transformModule(sourceCode, {...options(), polyfill: true}, (error, result) => {
-      expect(result).toEqual(objectContaining({isPolyfill: true}));
+      expect(result).toEqual(objectContaining({type: 'script'}));
       done();
     });
   });

packager/react-packager/src/ModuleGraph/worker/transform-module.js

@@ -75,9 +75,9 @@ function transformModule(
     callback(null, {
       code,
       file: filename,
-      isPolyfill: !!options.polyfill,
       hasteID: annotations.providesModule || annotations.provide || null,
       transformed,
+      type: options.polyfill ? 'script' : 'module',
     });
   });
 }
@@ -105,8 +105,8 @@ function transformJSON(json, options, callback) {
     code: json,
     file: filename,
     hasteID: value.name,
-    isPolyfill: false,
     transformed,
+    type: 'module',
   };
 
   if (basename(filename) === 'package.json') {