promise 那些事 ​

//某大厂面试题
Promise.resolve().then(() => {
    console.log(0);//第1层
    return Promise.resolve(4)
}).then((res) => {
    console.log(res)//第2层
})
Promise.resolve().then(() => {
    console.log(1);//第1层
}).then(() => {
    console.log(2);//第2层
}).then(() => {
    console.log(3);//第3层
}).then(() => {
    console.log(5);//第4层
}).then(() =>{
    console.log(6);//第5层
})

//进阶题目
Promise.resolve().then(() => {
	console.log(0);//2
	return new Promise(resolve => {
		console.log("newPromise")
		return resolve(4) //2
	}).then(res => {
			console.log('新增的 then 执行啦！')
			// Promise.resolve().then(()=>{
			// 	console.log("新增测试")
			// })	
			return res
		})
}).then(res => {
	console.log(res)
})
Promise.resolve().then(() => {
	console.log(1);//2
}).then(() => {
	console.log(,2);//3
}).then(() => {
	console.log(3);//4
}).then(() => {
	console.log(5);//5
}).then(() => {
	console.log(6);//6
})