function queue list var defer Deferred resolve while list length defer

function queue( list ) {
	var defer = $['Deferred']()['resolve']();
	while (list.length > 0) {
		defer = defer.then(list.shift());
	}
}


function sync1(){
	console.log("step 1");
}

function async1(){
	var defer = $['Deferred']();
	setTimeout(function(){
		console.log("step 2");
		defer.resolve(3)
	}, 2000);
	return defer['promise']();
}


function async2( N ){
	var defer = $['Deferred']();
	setTimeout(function(){
		console.log("step", N);
		defer.resolve();
	}, 2000);
	return defer['promise']();
}


function sync2(){
	console.log("END!1111");
}

queue([
	sync1,
	async1,
	async2,
	sync2
])