feat(router): add reuse support for angular 1.x router

Closes #3698

modules/angular1_router/build.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var fs = require('fs');
 var ts = require('typescript');
 
@@ -58,6 +60,10 @@ function main() {
           "});",
         "}));",
       "}",
+      "if (constructor.$routeConfig) {",
+        "constructor.annotations = constructor.annotations || [];",
+        "constructor.annotations.push(new angular.annotations.RouteConfig(constructor.$routeConfig));",
+      "}",
       "if (constructor.annotations) {",
         "constructor.annotations.forEach(function(annotation) {",
           "if (annotation instanceof RouteConfig) {",
@@ -70,7 +76,11 @@ function main() {
     "});",
 
     "var router = new RootRouter(registry, undefined, location, new Object());",
-    "$rootScope.$watch(function () { return $location.path(); }, function (path) { router.navigate(path); });",
+    "$rootScope.$watch(function () { return $location.path(); }, function (path) {",
+      "if (router.lastNavigationAttempt !== path) {",
+        "router.navigate(path);",
+      "}",
+    "});",
 
     "return router;"
   ].join('\n'));

modules/angular1_router/src/ng_outlet.js

@@ -134,11 +134,14 @@ function ngOutletDirective($animate, $injector, $q, $router, $componentMapper, $
 
     router.registerOutlet({
       commit: function (instruction) {
-        var next;
+        var next = $q.when(true);
         var componentInstruction = instruction.component;
         if (componentInstruction.reuse) {
-          // todo(shahata): lifecycle - onReuse
-          next = $q.when(true);
+          var previousInstruction = currentInstruction;
+          currentInstruction = componentInstruction;
+          if (currentController.onReuse) {
+            next = $q.when(currentController.onReuse(currentInstruction, previousInstruction));
+          }
         } else {
           var self = this;
           next = this.deactivate(instruction).then(function () {
@@ -159,8 +162,9 @@ function ngOutletDirective($animate, $injector, $q, $router, $componentMapper, $
         if (!currentInstruction ||
             currentInstruction.componentType !== componentInstruction.componentType) {
           result = false;
+        } else if (currentController.canReuse) {
+          result = currentController.canReuse(componentInstruction, currentInstruction);
         } else {
-          // todo(shahata): lifecycle - canReuse
           result = componentInstruction === currentInstruction ||
                    angular.equals(componentInstruction.params, currentInstruction.params);
         }

modules/angular1_router/test/ng_outlet_spec.js

@@ -358,6 +358,76 @@ describe('ngOutlet', function () {
   });
 
 
+  it('should reuse a component when the canReuse hook returns true', function () {
+    var log = [];
+    var cmpInstanceCount = 0;
+
+    function ReuseCmp() {
+      cmpInstanceCount++;
+      this.canReuse = function () {
+        return true;
+      };
+      this.onReuse = function (next, prev) {
+        log.push('reuse: ' + prev.urlPath + ' -> ' + next.urlPath);
+      };
+    }
+    ReuseCmp.$routeConfig = [{path: '/a', component: OneController}, {path: '/b', component: TwoController}];
+    registerComponent('reuse', 'reuse {<ng-outlet></ng-outlet>}', ReuseCmp);
+
+    $router.config([
+      { path: '/on-reuse/:number/...', component: ReuseCmp }
+    ]);
+    compile('outer { <div ng-outlet></div> }');
+
+    $router.navigate('/on-reuse/1/a');
+    $rootScope.$digest();
+    expect(log).toEqual([]);
+    expect(cmpInstanceCount).toBe(1);
+    expect(elt.text()).toBe('outer { reuse {one} }');
+
+    $router.navigate('/on-reuse/2/b');
+    $rootScope.$digest();
+    expect(log).toEqual(['reuse: on-reuse/1 -> on-reuse/2']);
+    expect(cmpInstanceCount).toBe(1);
+    expect(elt.text()).toBe('outer { reuse {two} }');
+  });
+
+
+  it('should not reuse a component when the canReuse hook returns false', function () {
+    var log = [];
+    var cmpInstanceCount = 0;
+
+    function NeverReuseCmp() {
+      cmpInstanceCount++;
+      this.canReuse = function () {
+        return false;
+      };
+      this.onReuse = function (next, prev) {
+        log.push('reuse: ' + prev.urlPath + ' -> ' + next.urlPath);
+      };
+    }
+    NeverReuseCmp.$routeConfig = [{path: '/a', component: OneController}, {path: '/b', component: TwoController}];
+    registerComponent('reuse', 'reuse {<ng-outlet></ng-outlet>}', NeverReuseCmp);
+
+    $router.config([
+      { path: '/never-reuse/:number/...', component: NeverReuseCmp }
+    ]);
+    compile('outer { <div ng-outlet></div> }');
+
+    $router.navigate('/never-reuse/1/a');
+    $rootScope.$digest();
+    expect(log).toEqual([]);
+    expect(cmpInstanceCount).toBe(1);
+    expect(elt.text()).toBe('outer { reuse {one} }');
+
+    $router.navigate('/never-reuse/2/b');
+    $rootScope.$digest();
+    expect(log).toEqual([]);
+    expect(cmpInstanceCount).toBe(2);
+    expect(elt.text()).toBe('outer { reuse {two} }');
+  });
+
+
   it('should not activate a component when canActivate returns false', function () {
     var spy = jasmine.createSpy('activate');
     var activate = registerComponent('activate', '', {