Is `setTimeout(func, 0)` and `setTimeout(func, 1)` considered the same?

Question

Here are some simple Javascript code using setTimeout:

function setTimeouts() {
  setTimeout(function() { console.log(2); }, 2);
  setTimeout(function() { console.log(1); }, 1);
  setTimeout(function() { console.log(0); }, 0);
}

for (var i = 0; i < 10; i++) {
  setTimeouts();
}

When I run it on Chrome or Node.js, the results are similar:

You can see all tasks with timeout 0 and 1 are before timeout 2, which is what I expected.

But the 0 and 1 are mixed with each other, seems like they have the same timeout. What I expected is all 0 before 1.

How to understand this?

Is this NodeJS or Google Chrome? Both have different timer implementations that are specified differently and in other places. — Benjamin Gruenbaum, Jun 22 '16 at 07:14
@Freewind:Any specific reasons why you expected `0` before `1`? — Sandeep Nayak, Jun 22 '16 at 07:25
@Freewind: This is a wonderful talk on the event loop in node which may answer your question..https://www.youtube.com/watch?v=8aGhZQkoFbQ — Sandeep Nayak, Jun 22 '16 at 07:31
I add an answer to that question: http://stackoverflow.com/a/37961816/342235 — Freewind, Jun 22 '16 at 07:55

score 0 · Answer 1 · answered Jun 22 '16 at 07:23

0

Actually, setTimeout's second parameters has minimum value limitation. For firefox the value is 4ms. If the passed value is less than minimum value, minimum will be used.

Regarding your question, I think this article is helpful: http://javascript.info/tutorial/events-and-timing-depth

answered Jun 22 '16 at 07:23

Ricky Jiao

531
4
10

Please run on firefox. The tasks with smaller timeout are executed first, even if they `<= 4` – Freewind Jun 22 '16 at 07:37

Is `setTimeout(func, 0)` and `setTimeout(func, 1)` considered the same?

1 Answers1