代码如下:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script type="text/javascript">
function queue(num){
return new Promise(resolve=>{
resolve();
}).then(
value=>{
let promise=Promise.resolve();
num.map(v=>{
promise=promise.then(_=>{
return new Promise(resolve=>{
//异步操作
setTimeout(() => {
console.log(v);
resolve();
}, 1000);
})
})
})
}
)
}
new Promise(resolve=>{
resolve();
}).then(
_=>{
let num=[1,2,3,4,5];
return Promise.resolve(num);
}
).then(
value=>{
queue(value);
}
).then(
value=>{
console.log("完成");
}
)
</script>
</body>
</html>
得到的结果:
问题:
如何实现在打印出1~5之后,再打印"完成"?
