How do you handle race conditions in useEffect fetching?
Use a cleanup flag that tracks whether the component is still mounted, or an AbortController to actually cancel the request. This ignores or cancels outdated responses when the component unmounts or dependencies change.
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More FAQs in useEffect Interview Questions for React Developers
It runs side effects after render, like data fetching, subscriptions, and DOM updates. The dependency array controls when it runs: after every render, only on mount, or when specific values change.
No array runs after every render. An empty array runs only on mount. An array with values runs when any of those values change. The array is the core of how you control effect timing.
It is the function returned from useEffect. React calls it before the next effect and on unmount, so you can tear down subscriptions, timers, and listeners, preventing memory leaks and stale updates.
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