closure

javascript closure

(function(){
	var sequence = Promise.resolve();
	for(var i = 0; i < 10 ; i++){
		const timeout = Math.random() * 1000;
		sequence = sequence.then((function(icopy){
			return new Promise((resolve, reject) => {setTimeout(() => { console.log(icopy); resolve();}, timeout);});
		})(i));
	}
})()


(function(){
	var sequence = Promise.resolve();
	[1,2,3,4,5,6].forEach(i => {
		const timeout = Math.random() * 1000;
		sequence = sequence.then((function(icopy){
			new Promise( (resolve, reject) => {  console.log(icopy); resolve();});
		})(i));
	});
})()



(function(){
	[1,2,3,4,5,6].forEach(i => {
		const timeout = Math.random() * 1000;
		setTimeout(() => console.log(i), timeout)

	});
	console.log("nihao");
})()

(function(){
	[1,2,3,4,5,6].forEach(function(i){
	const timeout = Math.random() * 1000;
		setTimeout(function(){console.log(i)}, timeout)

	});

})()


(function(){
	for(const i = 0; i < 10 ; i++){
		const timeout = Math.random() * 1000;
		setTimeout(() => console.log(i), timeout);
	}
})()