Using the useEffect hook to handle side effects
The useEffect hook allows you to execute code at different points in the lifecycle of a functional component. It's commonly used to perform data fetching, subscribe to events, or clean up side effects.
Synopsis
The useEffect hook allows you to execute code at different points in the lifecycle of a functional component. It's commonly used to perform operations such as data fetching, event subscriptions, DOM manipulation, and cleaning up side effects when the component unmounts.
It runs after the component renders and can be configured to run on every render, only on mount, or in response to changes in certain dependencies.
In the following example, useEffect is used to fetch data from an API when the component mounts, and returns a cleanup function that runs when the component unmounts.
Purpose
The useEffect hook facilitates the execution of side effects in functional components, eliminating the need to use class lifecycle methods likecomponentDidMount,componentDidUpdate, andcomponentWillUnmount.
- It allows making API requests to fetch or send data asynchronously.
- It facilitates event subscriptions and their subsequent cleanup to prevent memory leaks.
- It allows direct DOM manipulation when necessary.
- It's used to execute code in response to changes in specific dependencies, optimizing application performance.
- It manages the cleanup of side effects when a component unmounts, preventing unexpected behaviors.
Exercises
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