Implement Deferred object without using jquery

deferred, javascript, jquery, jquery-deferred

Solution

function Deferred(){
  this._done = [];
  this._fail = [];
}
Deferred.prototype = {
  execute: function(list, args){
    var i = list.length;

    // convert arguments to an array
    // so they can be sent to the
    // callbacks via the apply method
    args = Array.prototype.slice.call(args);

    while(i--) list[i].apply(null, args);
  },
  resolve: function(){
    this.execute(this._done, arguments);
  },
  reject: function(){
    this.execute(this._fail, arguments);
  }, 
  done: function(callback){
    this._done.push(callback);
  },
  fail: function(callback){
    this._fail.push(callback);
  }  
}


var v;

var setVal = function() {
    var d = new Deferred();
    setTimeout(function() {
        v = 'a value';
        d.resolve(this);
    }, 5000);
    return d;
};

setVal().done(function() {
    console.log('all done :' + v);
});

Problem

I want to implement basic Deferred object without using jQuery. Here i will be implementing only done and fail callbacks, with resolve and reject functions. and ofCourse associating `promise` method with this function. i am doing the following implementation in pure js (Edited) : ``` function Deferred() { var d = {}; d.resolve = function() { d.done(arguments); } d.reject = function() { d.fail(arguments); } d.promise = function() { var x = {}; x.done = function(args) { return args; } x.fail = function(args) { return args; } return x; } return d; } var v; var setVal = function() { var d = new Deferred(); setTimeout(function() { v = 'a value'; d.resolve(this); }, 5000); return d.promise(); }; setVal().done(function() { console.log('all done :' + v); }); ``` But the above gives the error : `Object #<Object> has no method 'fail'` I know the returned object 'd' of `Deferred()` function does not have method done(). And if i returns d.promise from `Deferred()` this will not have resolve and reject functions. Please point out what error i am making to achieve the simple objective of Deferred object. Here is the fiddle i am doing : http://jsfiddle.net/SyEmK/14/

Original source