When should we use the useEffect hook? Last Updated : 15 Feb, 2024 Comments Improve Suggest changes Like Article Like Report The useEffect hook in React is used to perform side effects in functional components. Side effects are actions that happen outside of the normal flow of the component, such as fetching data from an API, subscribing to events, or updating the DOM. When should we use the useEffect hook?Data Fetching:If your component needs to fetch data from an external source, such as an API, database, or local storage, useEffect is a good choice. You can use it to initiate the data fetching operation when the component mounts or when certain dependencies change.Subscriptions and Event Listeners:If your component needs to subscribe to events, such as keyboard events, mouse events, or WebSocket events, useEffect is useful. You can use it to set up event listeners when the component mounts and clean them up when the component unmounts.DOM Manipulation:If your component needs to interact with the DOM, such as updating the title of the document, adding or removing classes from elements, or setting up animations, useEffect is appropriate. You can use it to perform DOM manipulation after the component has been rendered.Setting up Timers or Intervals:If your component needs to perform actions at regular intervals, such as polling for updates or implementing a countdown timer, useEffect can be used. You can use it to set up timers or intervals when the component mounts and clear them when the component unmounts.Dependency Changes:If you need to run code in response to changes in certain dependencies, such as state variables or props, useEffect is handy. You can specify the dependencies as an array in the second argument of useEffect, and the effect will be re-run whenever any of those dependencies change.useEffect is used in functional components to handle side effects and perform tasks that are not directly related to rendering UI, such as data fetching, event handling, and DOM manipulation. It's a versatile hook that allows you to add behavior to your components in a declarative and easy-to-understand way. Comment More infoAdvertise with us Next Article When should we use the useEffect hook? F faheemakt6ei Follow Improve Article Tags : Web Technologies ReactJS MERN-QnA WebTech-FAQs Similar Reads When to use useCallback, useMemo and useEffect ? The useCallback hook is used to memoize the functions to prevent unnecessary re-renders, while useMemo is used to memoize the computed outputs, and useEffect performs sideEffects in a React application.The useCallback, useMemo, and useEffect are used to optimize the performance and manage the side e 8 min read What are hooks and when we use them ? Hooks are features that react provides us if we want to make functional components while creating a react web app. These features are alternatives to a few lifecycle methods like componentDidMount(), componentDidUpdate(), apart from this it gives us more flexibility to write maintainable code.Prereq 4 min read ReactJS useEffect Hook The useEffect hook is one of the most commonly used hooks in ReactJS used to handle side effects in functional components. Before hooks, these kinds of tasks were only possible in class components through lifecycle methods like componentDidMount, componentDidUpdate, and componentWillUnmount.What is 4 min read What is useDeferredValue hook and how to use it? In this article, we'll be learning about useDeferredValue hook. The `useDeferredValue` hook in React allows you to postpone updating a component of the UI. This can be beneficial for boosting performance when rendering a specific section of the UI is expensive, or when you wish to prioritize renderi 4 min read How do you use multiple useEffect in a component? useEffect is a hook used to perform side effects in function components. If you need to use multiple useEffect hooks in a single component, you can simply place them one after the other within your component function. Key Points for Using Multiple useEffect Hooks:Separation of Concerns: Each useEffe 2 min read Like