function bigHouse(){
			return new Promise(function(resolve,reject){
				setTimeout(function(){
					var n=Math.random();
					if(n>.5){
						resolve(" ")
					}else{
						reject(" ， ")
					}
				},2000)
			})
		}
		bigHouse()
		.then(res=>{
			console.log(res)
		})
		.catch(err=>{
			console.error(err)
		})

그림 순서 로드

버튼을 클릭하여 로드

<button type="button" id="btn"> </button>
var pics = [
		    "https://cdn.cnbj1.fds.api.mi-img.com/mi-mall/7bc54a61b927dd8c54ddd39a0acf0254.jpg?w=632&h=340",
		    "https://cdn.cnbj1.fds.api.mi-img.com/mi-mall/94c74e01afe50a86c3a87ff030b85781.jpg?w=632&h=340",
		    "https://cdn.cnbj1.fds.api.mi-img.com/mi-mall/816a66edef10673b4768128b41804cae.jpg?w=632&h=340"
		
		]
		function loadImage(url){
			return new Promise(function(resolve,reject){
				var img=document.createElement("img")
				img.src=url;
				img.onload=function(){resolve(img)}
				img.onerror=function(e){reject(e)}
			})
		}
btn.onclick=function(){
			loadImage(pics[0])
			.then(res=>{
				document.body.append(res)
			})
			.catch(err=>{
				console.log(err)
			})
		}
		loadImage(pics[0])
		.then(res=>{
			document.body.append(res)
			return loadImage(pics[1])
		})
		.then(res=>{
			document.body.append(res)
			return loadImage(pics[2])
		})
		.then(res=>{
			document.body.append(res)
		})
		.catch(err=>{console.log(err)})

가장 빠른 Promise 결과 - Promise를 반환합니다.race

//Promise.race Promise 
		Promise.race([loadImage(pics[0]),loadImage(pics[1]),loadImage(pics[2])])
		.then(res=>{
			document.body.append(res)
		})

등 두 개 이상의 ajax 데이터가 돌아와야 정상적으로 표시됩니다. - Promise.all

Promise.all([loadImage(pics[0]),loadImage(pics[1]),loadImage(pics[2])])
		.then(res=>{
			for(var k in res){
				document.body.append(res[k])
			}
		})