How to make a non-blocking sleep in javascript/jquery?

Question

You mean like a [timeout?](https://developer.mozilla.org/en/window.setTimeout) — Pekka, Oct 11 '11 at 16:32
@aF - you're going to need more detail about what you want before you can get a useful response. Are you looking for anything other than `setTimeout()`? — nrabinowitz, Oct 11 '11 at 16:36
@Dykam, `var halt=+new Date+3000;while(1){if(new Date>halt)break;}console.log('done after blocking for 3 seconds')` — davin, Oct 11 '11 at 16:39
Yeah, blocking sleep can be done. For example function `pausecomp(millis) { var date = new Date(); var curDate = null; do { curDate = new Date(); } while(curDate-date < millis); }` As for non-blocking obviously `setTimeout()` — freakish, Oct 11 '11 at 16:39
@davin, those are spin loops. Those aren't sleeps, just waits. Sleeps don't keep the CPU busy. The opposite really. — Dykam, Oct 11 '11 at 16:41
There is no non-blocking sleep in javascript. There are spin loops (eeck, horrible) and there are timeouts. Those are the two options. — jfriend00, Oct 11 '11 at 18:05

score 20 · Accepted Answer · edited Apr 29 '15 at 02:44

20

At the risk of stealing the answer from your commentors, use setTimeout(). For example:

var aWhile = 5000; // 5 seconds
var doSomethingAfterAWhile = function() {
  // do something
}
setTimeout( doSomethingAfterAWhile, aWhile );

edited Apr 29 '15 at 02:44

David

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answered Oct 11 '11 at 16:40

Lucas

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score 1 · Answer 2 · answered Jan 13 '22 at 19:55

since ECMAScript 2017 you can benefit from async/await:

https://jsfiddle.net/2tavp61e/

function delay (miliseconds) {
    return new Promise((resolve) => {
        window.setTimeout(() => {
            resolve();
        }, miliseconds);
    });
}

(async function () {
    console.log('A');
    await delay(2000);
    console.log('B');
})();

console.log('C');

"A" appears in the console first, "C" comes immediately after - which is proof that delay is non-blocking, and finally after two seconds there comes "B".

score 0 · Answer 3 · answered Jul 12 '21 at 09:28

this even works inside async function

      const util = require("util");
      const sleep = util.promisify(setTimeout);
      await sleep(5000); // waiting 5 seconds
      // now send response
      await res.status(401).send("incorrect username or password");
      return;

How to make a non-blocking sleep in javascript/jquery?

3 Answers3

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