![]() ![]() In this article, I explain how to use setTimeout(), including how you can use it to make a sleep function that will cause JavaScript to pause execution and wait between successive lines of code. ![]() The problem arises from misunderstanding setTimeout() as a sleep() function, when it actually works according to its own set of rules. You may have tried it at some point in a JavaScript loop and seen that setTimeout() seems to not work at all. Unfortunately, setTimeout() does not work quite as you might expect, depending on how you use it. In order to delay program execution for a fraction of a second, use usleep() as the sleep() function expects an int. In addition to using setTimeout and Promises with setTimeout, you can also use an NPM package to wait for X seconds using JavaScript. This helps with any application using Node.js sleep. “The setTimeout() method of the WindowOrWorkerGlobalScope mixin (and successor to tTimeout()) sets a timer which executes a function or specified piece of code once the timer expires.” - MDN Docs This is a better way to wait for 1 second in JavaScript, specifically Node.js, as it uses native code. const sleep (ms: number) > new Promise((resolve) > setTimeout(resolve, ms)) typescript. Delay executing part of an async function, by putting it to sleep, returning a Promise. There’s no sleep() method in JavaScript, so you try to use the next best thing, setTimeout(). Delays the execution of an asynchronous function. Delay in milliseconds Inside this method, you can specify how many milliseconds you want the function to delay. Here's an example: console. Wait using setTimeout One of the easiest way to achieve a 1 second delay is by using the setTimeout function that lives on the window global object. Some are better than others and some should only be used in specific circumstances. Let’s say you want to log three messages to Javascript’s console, with a delay of one second between each one. Function setTimeout () will set a timer and once the timer runs out, the function will run. There are quite a few ways to tell JavaScript to wait for 1 second. “In computing, sleep is a command in Unix, Unix-like and other operating systems that suspends program execution for a specified time.” - Wikipedia Javascript is single-threaded, so by nature there should not be a sleep function because sleeping will block the thread.
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