The useEffect Hook
Explore how to use the useEffect hook to handle side effects in React components. Learn how dependency arrays control effect execution, how to fetch data on mount, and how to perform cleanup tasks to optimize performance and prevent memory leaks. Practice with real examples like data fetching and theme toggling to build dynamic, responsive UIs.
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In any application, certain actions or “side effects” need to occur outside the regular rendering cycle. In the context of React and programming in general, side effects refer to operations or actions performed by a function that interact with or modify something outside the function’s scope, or affect the application in ways that are not purely computational. Examples include fetching data from an API, updating the DOM, or setting up timers.
In React, the useEffect Hook allows us to handle these side effects in functional components without relying on the component’s life cycle methods. This makes managing external interactions and cleanup tasks much more intuitive.
Understanding useEffect
The useEffect Hook is used for performing side effects in our components. It runs after the component renders and can optionally re-run when specific values (called dependencies) change.
What are dependencies?
Dependencies are the values or state variables that, when changed, trigger the re-execution of the effect function provided to useEffect. These values are listed in an array as the second parameter of ...