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使用本机（ES6）JavaScript承诺“等待”承诺或常规对象

[英]“Waiting” on either a promise or regular object using native(ES6) JavaScript promises

原文 2016-06-15 06:45:06 1 1 javascript/ promise/ ecmascript-6/ terminology

I played with promises a few times a few years ago using either jQuery or Q. I'm now quite rusty and want to learn and use the new native ES6 promises. 几年前，我使用jQuery或Q玩过Promise。我现在很生锈，想学习和使用新的原生ES6 Promise。

I seem to remember one neat concept where you can "wait" on something and not care whether it's a plain object or a promise. 我似乎记得一个简洁的概念，您可以在其中“等待”某物，而不在乎它是简单的对象还是承诺。 If it's a promise the callback is called when it asynchronously completes, if it's anything else the callback is called immediately - maybe the next tick. 如果它是一个承诺，则在异步完成时将调用该回调，否则，将立即调用该回调-可能是下一个刻度。

But I can't recall how this is done. 但是我不记得是怎么做到的。 I'm not sure if it has a name so it's proving difficult to Google for. 我不确定它是否有名称，因此对于Google来说很难。 I'm not sure if it's a standard feature across all JS promise implementations, or if it was just something only jQuery had. 我不确定这是否是所有JS promise实现中的标准功能，还是仅仅是jQuery所具有的功能。

What is this called? 这个叫什么？ Can I still do this with native promises? 我仍然可以使用本地承诺吗？ Where can I read up on it? 在哪里可以阅读？

1 个解决方案

Both jQuery's $.when() and ES6's Promise.all() exhibit the behaviour you refer to. jQuery的$.when() Promise.all() $.when()和ES6的Promise.all()展现了您所引用的行为。 Provide a promise and the function waits for the promise to resolve, but for any other value it returns immediately. 提供一个promise，函数等待该promise解析，但是对于其他任何值，它将立即返回。