是否有一个返回ES6承诺的setTimeout版本？ [英] Is there a version of setTimeout that returns an ES6 promise?

问题描述

类似于此问题，而不是询问如何承诺一般工作，我特意想知道：

什么是标准/最好的方式来包装 setTimeout ，返回一个 Promise ？我正在想像Angular的 $ timeout function ，但不是Angular。

解决方案

首先没有 - 没有内置这个。许多增强ES2015的图书馆承诺像蓝鸟鞭子一样。

我认为另一个答案使执行功能和延迟混淆，同时也造成无法取消的超时。我会简单地写：

  function delay（ms）{
 var ctr，rej，p = new Promise（function（resolve，reject）{
 ctr = setTimeout（resolve，ms）; 
 rej = reject; 
}）; 
 p.cancel = function（）{clearTimeout（ctr）; REJ（错误（ 取消））}; 
 return p; 
} 
  

然后你可以做：

$ pre> delay（1000）.then（/ * ... do whatever * /）;


或

  doSomething（）。then（function（）{return delay（1000）;}）然后（doSomethingElse）; 
  

如果我们只想要ES2015的基本功能，那就更简单了：

  let delay = ms =>新的Promise（r => setTimeout（r，ms））; 
  

Similar to this question, but rather than asking about how promises work in general, I specifically want to know:

What is the standard/best way to wrap setTimeout in something that returns a Promise? I'm thinking something like Angular's $timeout function, but not Angular specific.

解决方案

First of all no - there is no built in for this. Lots of libraries that enhance ES2015 promises like bluebird whip with it.

I think the other answer conflates executing the function and a delay, it also creates timeouts that are impossible to cancel. I'd write it simply as:

function delay(ms){
    var ctr, rej, p = new Promise(function (resolve, reject) {
        ctr = setTimeout(resolve, ms);
        rej = reject;
    });
    p.cancel = function(){ clearTimeout(ctr); rej(Error("Cancelled"))};
    return p; 
}

Then you can do:

delay(1000).then(/* ... do whatever */);

Or

 doSomething().then(function(){ return delay(1000); }).then(doSomethingElse);

If we only want the basic functionality in ES2015, it's even simpler as:

let delay = ms => new Promise(r => setTimeout(r, ms));

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