[Navigator]: Add method `indexOf` and `slice` to NavigationRouteStack

Libraries/CustomComponents/Navigator/Navigation/NavigationRouteStack.js

@@ -52,6 +52,16 @@ class RouteStack {
     return this._routes.get(index);
   }
 
+  indexOf(route: any): number {
+    return this._routes.indexOf(route);
+  }
+
+  slice(begin: ?number, end: ?number): RouteStack {
+    var routes = this._routes.slice(begin, end);
+    var index = Math.min(this._index, routes.size - 1);
+    return this._update(index, routes);
+  }
+
   /**
    * Returns a new stack with the provided route appended,
    * starting at this stack size.
@@ -71,7 +81,7 @@ class RouteStack {
       list.slice(0, this._index + 1).push(route);
     });
 
-    return new RouteStack(routes.size - 1, routes);
+    return this._update(routes.size - 1, routes);
   }
 
   /**
@@ -83,7 +93,7 @@ class RouteStack {
 
     // When popping, removes the rest of the routes past the current index.
     var routes = this._routes.slice(0, this._index);
-    return new RouteStack(routes.size - 1, routes);
+    return this._update(routes.size - 1, routes);
   }
 
   jumpToIndex(index: number): RouteStack {
@@ -92,11 +102,7 @@ class RouteStack {
       'index out of bound'
     );
 
-    if (index === this._index) {
-      return this;
-    }
-
-    return new RouteStack(index, this._routes);
+    return this._update(index, this._routes);
   }
 
   /**
@@ -129,7 +135,14 @@ class RouteStack {
     );
 
     var routes = this._routes.set(index, route);
-    return new RouteStack(this._index, routes);
+    return this._update(this._index, routes);
+  }
+
+  _update(index: number, routes: List): RouteStack {
+    if (this._index === index && this._routes === routes) {
+      return this;
+    }
+    return new RouteStack(index, routes);
   }
 }
 

Libraries/CustomComponents/Navigator/Navigation/__tests__/NavigationRouteStack-test.js

@@ -36,17 +36,17 @@ describe('NavigationRouteStack:', () => {
   // Basic
   it('gets index', () => {
     var stack = new NavigationRouteStack(1, ['a', 'b', 'c']);
-    expect(stack.index).toEqual(1);
+    expect(stack.index).toBe(1);
   });
 
   it('gets size', () => {
     var stack = new NavigationRouteStack(1, ['a', 'b', 'c']);
-    expect(stack.size).toEqual(3);
+    expect(stack.size).toBe(3);
   });
 
   it('gets route', () => {
     var stack = new NavigationRouteStack(0, ['a', 'b', 'c']);
-    expect(stack.get(2)).toEqual('c');
+    expect(stack.get(2)).toBe('c');
   });
 
   it('converts to an array', () => {
@@ -57,7 +57,7 @@ describe('NavigationRouteStack:', () => {
   it('creates a new stack after mutation', () => {
     var stack1 = new NavigationRouteStack(0, ['a', 'b']);
     var stack2 = stack1.push('c');
-    expect(stack1).not.toEqual(stack2);
+    expect(stack1).not.toBe(stack2);
   });
 
   it('throws at index out of bound', () => {
@@ -70,15 +70,57 @@ describe('NavigationRouteStack:', () => {
     }).toThrow();
   });
 
+  it('finds index', () => {
+    var stack = new NavigationRouteStack(0, ['a', 'b']);
+    expect(stack.indexOf('b')).toBe(1);
+    expect(stack.indexOf('c')).toBe(-1);
+  });
+
+  it('slices', () => {
+    var stack1 = new NavigationRouteStack(1, ['a', 'b', 'c', 'd']);
+    var stack2 = stack1.slice(1, 3);
+    expect(stack2).not.toBe(stack1);
+    expect(stack2.toArray()).toEqual(['b', 'c']);
+  });
+
+  it('may update index after slicing', () => {
+    var stack = new NavigationRouteStack(2, ['a', 'b', 'c']);
+    expect(stack.slice().index).toBe(2);
+    expect(stack.slice(0, 1).index).toBe(0);
+    expect(stack.slice(0, 2).index).toBe(1);
+    expect(stack.slice(0, 3).index).toBe(2);
+    expect(stack.slice(0, 100).index).toBe(2);
+    expect(stack.slice(-2).index).toBe(1);
+  });
+
+  it('slices without specifying params', () => {
+    var stack1 = new NavigationRouteStack(1, ['a', 'b', 'c']);
+    var stack2 = stack1.slice();
+    expect(stack2).toBe(stack1);
+  });
+
+  it('slices to from the end', () => {
+    var stack1 = new NavigationRouteStack(1, ['a', 'b', 'c', 'd']);
+    var stack2 = stack1.slice(-2);
+    expect(stack2.toArray()).toEqual(['c', 'd']);
+  });
+
+  it('throws when slicing to empty', () => {
+      expect(() => {
+        var stack = new NavigationRouteStack(1, ['a', 'b']);
+        stack.slice(100);
+      }).toThrow();
+  });
+
   // Push
   it('pushes route', () => {
     var stack1 = new NavigationRouteStack(1, ['a', 'b']);
     var stack2 = stack1.push('c');
 
-    expect(stack2).not.toEqual(stack1);
+    expect(stack2).not.toBe(stack1);
     expect(stack2.toArray()).toEqual(['a', 'b', 'c']);
-    expect(stack2.index).toEqual(2);
-    expect(stack2.size).toEqual(3);
+    expect(stack2.index).toBe(2);
+    expect(stack2.size).toBe(3);
   });
 
   it('throws when pushing empty route', () => {
@@ -101,27 +143,27 @@ describe('NavigationRouteStack:', () => {
   it('replaces routes on push', () => {
     var stack1 = new NavigationRouteStack(1, ['a', 'b', 'c']);
     var stack2 = stack1.push('d');
-    expect(stack2).not.toEqual(stack1);
+    expect(stack2).not.toBe(stack1);
     expect(stack2.toArray()).toEqual(['a', 'b', 'd']);
-    expect(stack2.index).toEqual(2);
+    expect(stack2.index).toBe(2);
   });
 
   // Pop
   it('pops route', () => {
     var stack1 = new NavigationRouteStack(2, ['a', 'b', 'c']);
     var stack2 = stack1.pop();
-    expect(stack2).not.toEqual(stack1);
+    expect(stack2).not.toBe(stack1);
     expect(stack2.toArray()).toEqual(['a', 'b']);
-    expect(stack2.index).toEqual(1);
-    expect(stack2.size).toEqual(2);
+    expect(stack2.index).toBe(1);
+    expect(stack2.size).toBe(2);
   });
 
   it('replaces routes on pop', () => {
     var stack1 = new NavigationRouteStack(1, ['a', 'b', 'c']);
     var stack2 = stack1.pop();
-    expect(stack2).not.toEqual(stack1);
+    expect(stack2).not.toBe(stack1);
     expect(stack2.toArray()).toEqual(['a']);
-    expect(stack2.index).toEqual(0);
+    expect(stack2.index).toBe(0);
   });
 
   it('throws when popping to empty stack', () => {
@@ -136,8 +178,8 @@ describe('NavigationRouteStack:', () => {
     var stack1 = new NavigationRouteStack(0, ['a', 'b', 'c']);
     var stack2 = stack1.jumpToIndex(2);
 
-    expect(stack2).not.toEqual(stack1);
-    expect(stack2.index).toEqual(2);
+    expect(stack2).not.toBe(stack1);
+    expect(stack2.index).toBe(2);
   });
 
   it('throws then jumping to index out of bound', () => {
@@ -157,21 +199,20 @@ describe('NavigationRouteStack:', () => {
     var stack1 = new NavigationRouteStack(1, ['a', 'b']);
     var stack2 = stack1.replaceAtIndex(0, 'x');
 
-    expect(stack2).not.toEqual(stack1);
+    expect(stack2).not.toBe(stack1);
     expect(stack2.toArray()).toEqual(['x', 'b']);
-    expect(stack2.index).toEqual(1);
+    expect(stack2.index).toBe(1);
   });
 
   it('replaces route at negative index', () => {
     var stack1 = new NavigationRouteStack(1, ['a', 'b']);
     var stack2 = stack1.replaceAtIndex(-1, 'x');
 
-    expect(stack2).not.toEqual(stack1);
+    expect(stack2).not.toBe(stack1);
     expect(stack2.toArray()).toEqual(['a', 'x']);
-    expect(stack2.index).toEqual(1);
+    expect(stack2.index).toBe(1);
   });
 
-
   it('throws when replacing empty route', () => {
     expect(() => {
       var stack = new NavigationRouteStack(1, ['a', 'b']);