How to Clear Timeout and interval Timers with React Hooks?

How to Clear Timeout and interval Timers with React Hooks?

Timers created with clearTimeout or setInterval are used often timers in React apps. To clearTimeout that are created with setTimeout , we should call clearTimeout(timer) in the useEffect. How to Clear Timeout and Interval Timers with React Hooks?

Timers created with setTimeout or setInterval are used often in React apps.

setTimeout lets us run code after a delay.

And setInterval lets us run code periodically.

To free up resources and to stop the timers from running, we should call clearTimeout to stop any timers created with setTimeout from running.

Likewise, we should call clearInterval to stop any timers created with setInterval from running.

In this article, we’ll look at the right way to clear timers created with these functions in React components created with hooks.

Clear Timers Created with setTimeout

To clear timers that are created with setTimeout , we should call clearTimeout in the useEffect callback is the function that’s run when the component unmounts.

The function that we return in the useEffect callback is run when the component unmounts, so we should put it there,.

For instance, we can write:

import React, { useEffect, useState } from "react";

export default function App() {
  const [loading, setLoading] = useState(true);
  useEffect(() => {
    const timer = setTimeout(() => setLoading(false), 1000);
    return () => {
  }, []);
  return <div>{loading ? "loading" : "hello"}</div>;

We have the loading state which is initially set to true .

Then we call useEffect with a callback.

In the callback, we call setTimeout with a callback that calls setLoading with false to set loading to false .

And the callback is run after 1000 milliseconds since the 2nd argument is 1000.

Also, we return a function that calls clearTimeout with timer to clear the timer.

programming javascript technology

What is Geek Coin

What is GeekCash, Geek Token

Best Visual Studio Code Themes of 2021

Bootstrap 5 Tutorial - Bootstrap 5 Crash Course for Beginners

Nest.JS Tutorial for Beginners

Hello Vue 3: A First Look at Vue 3 and the Composition API

JavaScript: Chessboard Program

Exercise from Eloquent JavaScript. Today, we will write a function that forms a chessboard. You can find the exercise in the Eloquent Javascript book (3rd edition, chapter 2; Program Structure). Write a program that creates a string that represents an 8×8 grid, using newline characters to separate lines. At each position of the grid there is either a space or a “#” character. The characters should form a chessboard.

Learning JavaScript: Development Environments for JavaScript Programming

One of the nice things about learning JavaScript these days is that there is a plethora of choices for writing and running JavaScript code. In this article, I’m going to describe a few of these environments and show you the environment I’ll be using in this series of articles.

Learning JavaScript: Data Types and Variables

To paraphrase the title of an old computer science textbook, “Algorithms + Data = Programs.” The first step in learning a programming language such as JavaScript is to learn what types of data the language can work with. The second step is to learn how to store that data in variables. In this article I’ll discuss the different types of data you can work with in a JavaScript program and how to create and use variables to store and manipulate that data.

[ Professor JavaScript ]: Introduction

Professor JavaScript is a JavaScript online learning courses YouTube Channel. Students can learn how to develop codes with JavaScript from basic to advanced levels through the online courses in this YouTube channel.

Hire Dedicated JavaScript Developers -Hire JavaScript Developers

Hire dedicated JavaScript Developers who are proficient in AngularJS, ReactJS, NodeJS, & VueJS frameworks. Get flexible hiring models as per your business requirements.