What is a memory leak in the context of React’s useEffect and how do you prevent it?

Question

React Developer — Hard

What is a memory leak in the context of React’s useEffect and how do you prevent it?

Accepted Answer

A memory leak in React's useEffect occurs when an async operation tries to update state on an unmounted component. This can be prevented by returning a cleanup function from useEffect to cancel the operation or by setting an isMounted flag.