高效的秒表 [英] Efficient Stopwatch

问题描述

您好我正在使用javascript编写秒表实用程序，我对效率和开销有疑问。我有两种方法考虑制作秒表：

Hi I'm programming a stopwatch utility in javascript and I have a question about efficiency and overhead. There are two ways I have considered making the stopwatch:

1.存储一个开始日期并不断测量自该日期以来的毫秒数。

1.Store a start Date and constantly measure the number of milliseconds it has been since that date.

2.创建一个整数并以设定的间隔递增其值。

2.Create an integer and increment its value at a set interval.

我想知道哪个是最有效的。此外，我不确定选项＃2是否会非常准确，如果有人对此有任何意见也会很棒。

I want to know which is most efficient. Also, I'm not sure if option #2 would be very accurate, if anyone has any input about this that would be awesome as well.

推荐答案

正如其他人所说，请选择＃1。如果你想要一个每秒（或分钟或其他）滴答的时钟，你应该估计到下一个滴答的时间，以便在正确的时间之后几毫秒调用 setTimeout ，例如在下一整秒后运行：

As others have said, go with #1. If you want a clock that ticks each second (or minute or whatever) you should estimate the time to the next "tick" so that setTimeout is called a few ms after the right time, e.g. to run just after the next whole second:

var d = new Date();
var interval = 1020 - d.getMilliseconds();
setTimeout(fn, interval);

这样一来，如果一个电话的执行因系统繁忙而延迟，那么下一个应该仍然是在下一整秒后大约20ms调用。

That way if execution for one call is delayed by the system being busy, the next one should still be called about 20ms after the next whole second.

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