Connection failure: Connection is no longer needed.Įven if you have many cases to stop the timer for various reasons, error handling can be done in only one place in this way. If you want to do something 1 second later, setTimeout can be used.

Usage of cancellable sleep Usage of setTimeout.

log ( 'Hello' ) setTimeout ( ( ) => delayedGreeting ( ) console. The term X here refers to the number of seconds. The time given in the parameter is in the unit of ms. The standard way of creating a delay in JavaScript is to use its setTimeout method. JavaScript provides a built-in method setTimeout() to wait X seconds based on user needs. Use the setTimeout () to Wait for X Seconds in JavaScript The asynchronous setTimeout () method is one of the higher-order functions that takes a callback function as an argument, and it executes that function after the input time elapsed. 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?. JavaScript in Plain English Coding Won’t Exist In 5 Years. 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. 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'

Javascript sleep 1 second