simple deferred object implementation, library & platform agnostic

deferred.js

var newDefered = function(){
	var state = 0 ; // 0 - unresolved, 1 - resolved, 2 - rejected
	var resolveCallbacks = [] ;
        var resolveArgs = [] ;
	var rejectCallbacks = [] ;
	var rejectArgs = [] ;

	var execute = function( callbacks, args ){
		while( callbacks.length !== 0 ){
			callbacks.shift().call( {}, args ) ;
		}
	} ;

	var done = function( callback ){
		resolveCallbacks.push( callback );	
		if( state === 1 ){
			execute( resolveCallbacks , resolveArgs );
		}
		return that ;
	} ;
	var fail = function( callback ){
		rejectCallbacks.push( callback );
		if( state === 2 ){
			execute( rejectCallbacks, rejectCallbacks );
		}
		return that ;
	} ;

	var resolve = function(){
		if( state !== 0 ) {
			throw Error( 'State already resolved' );
		}
		state = 1 ;
		resolveArgs = Array.prototype.slice.call( arguments );
		execute( resolveCallbacks , resolveArgs ) ;
		return that ;
	} ;
	var reject = function(){
		if( state !== 0 ){
			throw Error( 'State already resolved' );
		}
		state = 2 ;
		rejectArgs = Array.prototype.slice.call( arguments );
		execute( resolveCallbacks , rejectArgs ) ;
		return that ;
	} ;
	var isRejected = function(){
		return state === 2 ;
	} ;
	var isResolved = function(){
		return state === 1 ;
	} ;

	var getPromise = function(){
		return promise ;
	};

	// public module api
	var promise = {
		isRejected : isRejected ,
		isResolved : isResolved ,
		done : done ,
		fail : fail 
	}
	var that = {
		isRejected : isRejected ,
	        isResolved : isResolved ,
		resolve : resolve ,
		reject : reject ,
		done : done ,
		fail : fail ,
		promise : getPromise 
	} ;
	return that ;
} ;