feat($timeout): overload service API.

Provide an overload for $timeout that doesn't take a function.

Closes #9176

Author: vasileorza

src/ng/timeout.js

@@ -4,7 +4,8 @@
 function $TimeoutProvider() {
   this.$get = ['$rootScope', '$browser', '$q', '$$q', '$exceptionHandler',
        function($rootScope,   $browser,   $q,   $$q,   $exceptionHandler) {
-    var deferreds = {};
+
+     var deferreds = {};
 
 
      /**
@@ -19,20 +20,35 @@ function $TimeoutProvider() {
       * The return value of registering a timeout function is a promise, which will be resolved when
       * the timeout is reached and the timeout function is executed.
       *
+      * Additionally, the wrapper function can also be used without a target 'fn' function in order
+      * to generate a delayed promise.
+      *
       * To cancel a timeout request, call `$timeout.cancel(promise)`.
       *
       * In tests you can use {@link ngMock.$timeout `$timeout.flush()`} to
       * synchronously flush the queue of deferred functions.
       *
-      * @param {function()} fn A function, whose execution should be delayed.
+      * @param {function()} fn A function, whose execution should be delayed. This argument is
+      *   optional and can be skipped if required.
       * @param {number=} [delay=0] Delay in milliseconds.
       * @param {boolean=} [invokeApply=true] If set to `false` skips model dirty checking, otherwise
       *   will invoke `fn` within the {@link ng.$rootScope.Scope#$apply $apply} block.
       * @returns {Promise} Promise that will be resolved when the timeout is reached. The value this
       *   promise will be resolved with is the return value of the `fn` function.
       *
       */
-    function timeout(fn, delay, invokeApply) {
+    function timeout() {
+      var fn, delay, invokeApply;
+      if (isFunction(arguments[0])) {
+        fn = arguments[0],
+        delay = arguments[1],
+        invokeApply = arguments[2];
+      } else {
+        fn = noop,
+        delay = arguments[0],
+        invokeApply = false;
+      }
+
       var skipApply = (isDefined(invokeApply) && !invokeApply),
           deferred = (skipApply ? $$q : $q).defer(),
           promise = deferred.promise,

test/ng/timeoutSpec.js

@@ -48,6 +48,17 @@ describe('$timeout', function() {
   }));
 
 
+  it('should NOT call $apply if no callback function is used', inject(function($timeout, $rootScope) {
+    var applySpy = spyOn($rootScope, '$apply').andCallThrough();
+
+    $timeout().then(function() {});
+    expect(applySpy).not.toHaveBeenCalled();
+
+    $timeout.flush();
+    expect(applySpy).not.toHaveBeenCalled();
+  }));
+
+
   it('should NOT call $evalAsync or $digest if invokeApply is set to false',
       inject(function($timeout, $rootScope) {
     var evalAsyncSpy = spyOn($rootScope, '$evalAsync').andCallThrough();
@@ -69,6 +80,10 @@ describe('$timeout', function() {
     $timeout(noop, 123);
     expect(defer.callCount).toEqual(1);
     expect(defer.mostRecentCall.args[1]).toEqual(123);
+
+    $timeout(456);
+    expect(defer.callCount).toEqual(2);
+    expect(defer.mostRecentCall.args[1]).toEqual(456);
   }));
 
 
@@ -81,6 +96,14 @@ describe('$timeout', function() {
 
     $timeout.flush();
     expect(log).toEqual(['timeout', 'promise success: buba']);
+
+    var promise = $timeout();
+
+    promise.then(function(value) { log('promise success'); }, log.fn('promise error'));
+    expect(log).toEqual(['timeout', 'promise success: buba']);
+
+    $timeout.flush();
+    expect(log).toEqual(['timeout', 'promise success: buba', 'promise success']);
   }));
 
 
@@ -165,19 +188,24 @@ describe('$timeout', function() {
       var task1 = jasmine.createSpy('task1'),
           task2 = jasmine.createSpy('task2'),
           task3 = jasmine.createSpy('task3'),
-          promise1, promise3;
+          task4 = jasmine.createSpy('task4'),
+          promise1, promise3, promise4;
 
       promise1 = $timeout(task1);
       $timeout(task2);
       promise3 = $timeout(task3, 333);
+      promise4 = $timeout(333);
+      promise3.then(task4);
 
-      $timeout.cancel(promise3);
       $timeout.cancel(promise1);
+      $timeout.cancel(promise3);
+      $timeout.cancel(promise4);
       $timeout.flush();
 
       expect(task1).not.toHaveBeenCalled();
       expect(task2).toHaveBeenCalledOnce();
       expect(task3).not.toHaveBeenCalled();
+      expect(task4).not.toHaveBeenCalled();
     }));