let Promise = function(cb) {
	this.q = [];

	cb(this.resolve.bind(this));
};

Promise.prototype.resolve = function(data) {
	this.q.pop()(data);
};

Promise.prototype.then = function(cb) {
	this.q.push(cb);
};

new Promise(function(resolve) {
	setTimeout(function() {
		resolve(10);
	}, 500);
}).then(function(res) {
	console.log('res is', res);
});