Add error backs for promises.

This commit is contained in:
Brendan Dahl 2012-01-04 16:13:53 -08:00
parent dba1a7dc6f
commit dddcb9c91b
2 changed files with 48 additions and 12 deletions

View file

@ -206,6 +206,8 @@ var Promise = (function PromiseClosure() {
*/
function Promise(name, data) {
this.name = name;
this.isRejected = false;
this.error = null;
// If you build a promise and pass in some data it's already resolved.
if (data != null) {
this.isResolved = true;
@ -216,6 +218,7 @@ var Promise = (function PromiseClosure() {
this._data = EMPTY_PROMISE;
}
this.callbacks = [];
this.errbacks = [];
};
/**
* Builds a promise that is resolved when all the passed in promises are
@ -282,6 +285,9 @@ var Promise = (function PromiseClosure() {
if (this.isResolved) {
throw 'A Promise can be resolved only once ' + this.name;
}
if (this.isRejected) {
throw 'The Promise was already rejected ' + this.name;
}
this.isResolved = true;
this.data = data || null;
@ -292,7 +298,24 @@ var Promise = (function PromiseClosure() {
}
},
then: function promiseThen(callback) {
reject: function proimseReject(reason) {
if (this.isRejected) {
throw 'A Promise can be rejected only once ' + this.name;
}
if (this.isResolved) {
throw 'The Promise was already resolved ' + this.name;
}
this.isRejected = true;
this.error = reason || null;
var errbacks = this.errbacks;
for (var i = 0, ii = errbacks.length; i < ii; i++) {
errbacks[i].call(null, reason);
}
},
then: function promiseThen(callback, errback) {
if (!callback) {
throw 'Requiring callback' + this.name;
}
@ -301,8 +324,13 @@ var Promise = (function PromiseClosure() {
if (this.isResolved) {
var data = this.data;
callback.call(null, data);
} else if (this.isRejected && errorback) {
var error = this.error;
errback.call(null, error);
} else {
this.callbacks.push(callback);
if (errback)
this.errbacks.push(errback);
}
}
};