From a207665dad69248139b150cd3fe8ba13059bffb4 Mon Sep 17 00:00:00 2001 From: bolasblack Date: Tue, 6 Aug 2013 17:48:32 +0800 Subject: feat($q): add shorthand for defining promise error handlers Now we can instead this promise.then(null, errorHandler) with this promise.catch(errorhandler) Closes #2048 Closes #3476 --- src/ng/q.js | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) (limited to 'src/ng/q.js') diff --git a/src/ng/q.js b/src/ng/q.js index b68660d5..e3c64645 100644 --- a/src/ng/q.js +++ b/src/ng/q.js @@ -91,6 +91,8 @@ * This method *returns a new promise* which is resolved or rejected via the return value of the * `successCallback` or `errorCallback`. * + * - `catch(errorCallback)` – shorthand for `promise.then(null, errorCallback)` + * * - `always(callback)` – allows you to observe either the fulfillment or rejection of a promise, * but to do so without modifying the final value. This is useful to release resources or do some * clean-up that needs to be done whether the promise was rejected or resolved. See the [full @@ -128,25 +130,25 @@ * you can treat promises attached to a scope as if they were the resulting values. * - Q has many more features than $q, but that comes at a cost of bytes. $q is tiny, but contains * all the important functionality needed for common async tasks. - * + * * # Testing - * + * *
  *    it('should simulate promise', inject(function($q, $rootScope) {
  *      var deferred = $q.defer();
  *      var promise = deferred.promise;
  *      var resolvedValue;
- * 
+ *
  *      promise.then(function(value) { resolvedValue = value; });
  *      expect(resolvedValue).toBeUndefined();
- * 
+ *
  *      // Simulate resolving of promise
  *      deferred.resolve(123);
  *      // Note that the 'then' function does not get called synchronously.
  *      // This is because we want the promise API to always be async, whether or not
  *      // it got called synchronously or asynchronously.
  *      expect(resolvedValue).toBeUndefined();
- * 
+ *
  *      // Propagate promise resolution to 'then' functions using $apply().
  *      $rootScope.$apply();
  *      expect(resolvedValue).toEqual(123);
@@ -267,8 +269,13 @@ function qFactory(nextTick, exceptionHandler) {
 
           return result.promise;
         },
+
+        "catch": function(callback) {
+          return this.then(null, callback);
+        },
+
         always: function(callback) {
-          
+
           function makePromise(value, resolved) {
             var result = defer();
             if (resolved) {
@@ -278,14 +285,14 @@ function qFactory(nextTick, exceptionHandler) {
             }
             return result.promise;
           }
-          
+
           function handleCallback(value, isResolved) {
-            var callbackOutput = null;            
+            var callbackOutput = null;
             try {
               callbackOutput = (callback ||defaultCallback)();
             } catch(e) {
               return makePromise(e, false);
-            }            
+            }
             if (callbackOutput && callbackOutput.then) {
               return callbackOutput.then(function() {
                 return makePromise(value, isResolved);
@@ -296,7 +303,7 @@ function qFactory(nextTick, exceptionHandler) {
               return makePromise(value, isResolved);
             }
           }
-          
+
           return this.then(function(value) {
             return handleCallback(value, true);
           }, function(error) {
-- 
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