log ( 'Hello' ) setTimeout ( ( ) => delayedGreeting ( ) console. The standard way of creating a delay in JavaScript is to use its setTimeout method. Now that we have a better understanding of JavaScript’s execution model, let’s have a look at how JavaScript handles delays and asynchronous operations. You Might Not Actually Need a JS Sleep Function If any of this is news to you, you should watch this excellent conference talk: What the heck is the event loop anyway?. Rather, it will continue on its way, output “Hello!” to the console, then when the request returns a couple of hundred milliseconds later, it will output the number of repos. It will not, however, wait for the request to complete. The JavaScript interpreter will encounter the fetch command and dispatch the request. This is because fetching data from an API is an asynchronous operation in JavaScript. If you run this code, it will output “Hello!” to the screen, then the number of public repos attributed to my GitHub account. Execution goes from top to bottom.Ĭontrast that with the equivalent JavaScript version: fetch ( '' ). It then parses the response, outputs the number of public repos attributed to my GitHub account and finally prints “Hello!” to the screen.

get (uri ) )Īs one might expect, this code makes a request to the GitHub API to fetch my user data. The callback function is the code that you want to execute after the specified delay.Understanding JavaScript’s Execution Modelīefore we get going, it’s important to make sure we understand JavaScript’s execution model correctly.Ĭonsider the following Ruby code: require 'net/http' require 'json' To use setTimeout to wait for one second in JavaScript, you would pass two arguments to the function: a callback and an integer delay, in milliseconds. But of course, this can be generalized to wait any amount of time as well. In this tutorial, we'll learn how to use setTimeout to wait for one second in JavaScript. One of the ways to accomplish this is by using the setTimeout function, which allows you to specify a delay, in milliseconds, before executing a given callback function.

This can be useful for creating delays, like for periodically making an AJAX request, running animations, or even to simply allowing a certain process to complete before moving on. The time to delay in script execution is specified. In JavaScript, waiting a specific amount of time before executing a function or piece of code is a common requirement. You can simply use the setTimeout() method to sleep or wait before continuing to run the code in JavaScript.

Javascript sleep 1 second