Creating a loop using setTimeout up to the minute, then every five minutes

Question

I would like to check the minute, until I get to :00, :05, :10, etc minutes, then set to 5 minutes (on the minute) and continue on during the application. Is there a better way to do this? Do I need a clearTimeout? Please help and thanks!

Goal: Check the minutes, once on 00, 05, 10, 15, 30, etc change to 5 minute interval and keep running.

// Set to 1 minute initially.
let interval = 60000;

function timeCheck() {
  const date = getNow();
  console.log("checking...", `${dayjs(date).hour()}:${dayjs(date).minute()}:${dayjs(date).second()}`);
  // Check browser time in minutes for 00, 05, 10, 15, 20, etc.
  if (dayjs(date).minute() % 5 === 0) {
    // Set to 5 minute.
    interval = 300000;
    ...
  }
  setTimeout(timeCheck, interval);
}

clearTimeout(timeCheck);
timeCheck();

`clearTimeout(timeCheck)` doesn't do anything. clearTimeout works for timer id which you can get from `let id = setTimeout(...)`. — n1md7, Jan 26 '22 at 20:00
Why does it have to be `setTimeout` and not, say, `setInterval`? — Heretic Monkey, Jan 26 '22 at 20:01
I can't dynamically change the delay on `setInterval`. @HereticMonkey — n8tron, Jan 26 '22 at 20:02
@n8tron Yes you can, by setting a new interval and clearing, see my answer — Samathingamajig, Jan 26 '22 at 20:03
...which is the same as a duplicate question [How to pass a variable to setInterval?](https://stackoverflow.com/q/25734518/215552) — Heretic Monkey, Jan 26 '22 at 20:05
This is not the same as that question linked, as this does not need to change the interval more than once — Samathingamajig, Jan 26 '22 at 20:09
I didn't say that question is the same as this one. I was responding to the "I can't dynamically change the delay on `setInterval`" comment. — Heretic Monkey, Jan 26 '22 at 20:11
Does this answer your question? [call function on the minute every minute](https://stackoverflow.com/questions/20502277/call-function-on-the-minute-every-minute) — Heretic Monkey, Jan 26 '22 at 20:13
In other words, just run your code every minute. When the minute is 0, 5, 10, 15, whatever, do the thing. Yes, you'll be executing an `if` condition every second, but checking if the minute hand is at a mark evenly divisible by 5 shouldn't take JavaScript too long :). — Heretic Monkey, Jan 26 '22 at 20:16

Samathingamajig · Answer 1 · 2022-01-26T23:09:18.277

0

console.log("Starting...");

const task = () => {
  console.log("do something");
}

let minuteInterval;

const checkMinuteInterval = () => {
  const date = new Date();
  if (date.getMinutes() % 5 === 0) {
    clearInterval(minuteInterval);
    task();
    setInterval(task, 1000 * 60 * 5);
  } else {
    console.log("Not on multiple of 5");
  }
};

minuteInterval = setInterval(checkMinuteInterval, 1000 * 60);
checkMinuteInterval();

edited Jan 26 '22 at 23:09

answered Jan 26 '22 at 20:01

Samathingamajig

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We have hundreds, if not thousands, of questions with answers regarding the use of `setTimeout` and `setInterval`. The least you can do is provide explanation of how this code differs from those. – Heretic Monkey Jan 26 '22 at 20:05
This is what OP wants in the structure they want it. Only slightly modified from OP's, and readable, so it doesn't need an explanation. – Samathingamajig Jan 26 '22 at 20:07
@Samathingamajig -- This is great, but `console.log("do something")` isn't running inside of the nested `setInterval` -- Am I missing something? I'll run it again to test. Thanks so much! – n8tron Jan 26 '22 at 23:03
@n8tron because of how setInterval works, it will not fire for the first round of 5 minutes. You can get around that with my edit coming soon – Samathingamajig Jan 26 '22 at 23:05

score 0 · Accepted Answer · answered Jan 26 '22 at 23:17

A completely different approach, since this seems like an XY problem, is to just have an interval for every minute, check if it's a multiple of 5, if so do something, otherwise just break out of the function. (As suggested by @Heretic Monkey)

console.log("Starting...");

const task = () => {
  if ((new Date()).getMinutes % 5 !== 0) {
    console.log("Not a multiple of 5 minutes");
    return; // would just be return; in production code
  }
  
  console.log("Do something")
  // rest of function...
}

task();
setInterval(task, 1000 * 60);

The idea I got from the posted duplicate, @Samathing. – Heretic Monkey Jan 26 '22 at 23:52 — Heretic Monkey, Jan 26 '22 at 23:52

Creating a loop using setTimeout up to the minute, then every five minutes

2 Answers2