The useEffect hook in React is used for handling side effects in functional components. Side effects can include data fetching, subscriptions, manual DOM manipulations, or anything that involves interaction with the external world. The useEffect hook is designed to replace lifecycle methods like componentDidMount, componentDidUpdate, and componentWillUnmount in class components.
The useEffect hook takes two arguments: a function and an array of dependencies.
The function passed to useEffect contains the code that you want to run as a side effect.
The array of dependencies is optional. If it’s provided, the effect will only re-run if any of the dependencies change. If the array is empty (), the effect will run only once after the initial render.
Keep in mind that if you’re using state or props inside the useEffect callback, and those values might change between renders, you should include those variables in the dependencies array to ensure that the effect runs with the latest values.
Remember to handle cleanup within the cleanup function if your effect involves any asynchronous tasks, subscriptions, or other resource allocations to avoid memory leaks.