How to set loop with pause in between each log

Question

How could I make a loop that pauses for a set amount of time before repeating? I tried using setTimeout inside of a while loop but that didn't work.

Answer 1

JavaScript is monothreaded, so blocking is to be avoided, that is why so much effort was pourred into the language to standardise Promise and add async / await

This allow to pause code execution without blocking, here how you do it:

// Only available in Node v15+
import { setTimeout as pause } from 'timers/promises'

// if not in node:
const pause = delay => new Promise(s => setTimeout(s, delay))

async function sayHelloEverySeconds() {
  while (true) {
    await pause(1000) // 1 sec
    console.log('hello')
  }
}

sayHelloEverySeconds()

But for this exact function, it would be simpler to use setInterval directly:

setInterval(() => console.log('hello'), 1000)

this will execute the function every seconds

Answer 2

You don't need to use async/await functions or promises or a while loop. Call a function and have setTimeout call the function again after a set amount of time.

 function loop(count = 0) { console.log(count); setTimeout(loop, 1000, ++count); } loop();

Answer 3

If you do want to implement the setInterval (which I don't recommend), do it like this:

 async function sayHelloEverySeconds() { while (true) { await new Promise((res, rej) => { setTimeout(() => { console.log('hello') res() }, 1000) // 1 sec }) } } sayHelloEverySeconds()

Of course, as said above, use the setInterval(callback, timeInMS)