javascript使用yield模擬await功能

yield.js

function requestAsync(path,thread){
	var q = new XMLHttpRequest();
	q.open('get','test.json');
	q.onload = function(){
		requestAsync['result'] = JSON.parse(q.response);
		thread.next();//回呼
	}
	q.send();
}

function async(func,args){
	var result = func.apply(func,args);
	func["thread"] = result;//thread
	result.next();
}

async(function*(){
	yield requestAsync('test.json',this.thread);
	var temp = requestAsync.result;//取得結果後執行
	console.log(temp.message1 + " " + temp.message2);
});