等待.forEach()完成的最佳方法 [英] Best way to wait for .forEach() to complete

问题描述

有时，我需要等待.forEach()方法完成，主要是在'loader'函数上.这就是我这样做的方式:

Sometimes I need to wait for a .forEach() method to finish, mostly on 'loader' functions. This is the way I do that:

$q.when(array.forEach(function(item){ 
    //iterate on something 
})).then(function(){ 
    //continue with processing 
});

我忍不住觉得这不是等待.forEach()完成的最佳方法.最好的方法是什么?

I can't help but feel that this isn't the best way to wait for a .forEach() to finish. What is the best way to do this?

推荐答案

如果forEach中没有异步代码，则forEach不是异步的，例如以下代码:/p>

If there is no asynchronous code inside the forEach, forEach is not asynchronous, for example in this code:

array.forEach(function(item){ 
    //iterate on something 
});
alert("Foreach DONE !");

forEach完成后，您将看到警报.

you will see the alert after forEach finished.

否则(内部有一些异步的东西)，可以将forEach循环包装在

Otherwise (You have something asynchronous inside), you can wrap the forEach loop in a Promise:

var bar = new Promise((resolve, reject) => {
    foo.forEach((value, index, array) => {
        console.log(value);
        if (index === array.length -1) resolve();
    });
});

bar.then(() => {
    console.log('All done!');
});

信用:@ rolando-benjamin-vaz-ferreira

Credit: @rolando-benjamin-vaz-ferreira

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