Basic promise implementation

promise.js

Promise = function(){ 
        this.result = undefined;
        this.complete = false
	this.failure = false;
	this.onFailure = [];
	this.onSuccess = [];
};

Promise.prototype.resolve = function(fnResult){
	if (this.complete){
		throw "Already resolved";
	}

	try
		{
			this.result = fnResult;
			this.complete = true
			for(var i = 0; i < this.onSuccess.length; i++){
				this.onSuccess.shift()(fnResult);
			}
		}
	catch(err)
		{
			this.failure = true;
			for(var i = 0; i < this.onFailure.length; i++){
				this.onFailure.shift()(err);
			}
		}
};

Promise.prototype.success = function(fn){
	if(this.complete){ 
		return fn(this.result);
	} else {
		this.onSuccess.push(fn);
	}
};

Promise.prototype.error = function(fn){
	if(this.failure === true){
		return fn(this.result);
	} else {
		this.onFailure.push(fn);
	}
};



var foo = new Promise();
var bar = new Promise();

foo.resolve('hello');

setTimeout(function(){
  bar.resolve('world');
}, 500);

foo.success(function(result){
  console.log(result);
});

bar.success(function(result){
  console.log(result);
});