setTimeout返回什么？ [英] What does setTimeout return?

问题描述

我很好奇setTimeout返回的是什么。所以我做了一个快速测试：

I was curious that what does setTimeout return. So I did a quick test:

var thing = setTimeout(function(){},1);

令我惊讶的是它给了我一个号码。 1351 每次都不同。

And what surprise me is that it gave me a number. 1351 Each time is different.

所以它真的只返回一个数字吗？所以我也可以这样做吗？

So is it really all it returns is a number? So I can actually do this as well?

clearTimeout(1351);

非常混乱......

Very confusing...

推荐答案

这是一个句柄（唯一标识符）。当您创建超时时，JavaScript运行时将句柄与您创建的超时相关联，并且它可以通过句柄 setTimeout（）返回来识别超时。当您运行 clearTimeout（）时，它会通过查看您传入的唯一句柄知道您正在谈论的超时。

It's a handle (a unique identifier). When you create a timeout, the JavaScript runtime associates a handle with the timeout you created, and it can identify that timeout by the handle setTimeout() returns. When you run clearTimeout(), it will know what timeout you're talking about by looking at the unique handle you pass in.

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