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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