What is a stale closure in React hooks?
Tests closures and hook dependencies. A strong answer defines stale closure as capturing an outdated variable, shows a useEffect interval with stale state, and fixes it with dependencies and cleanup. Red flag: omitting cleanup or using refs blindly.
Tests deep understanding of JavaScript closures and React's data flow. A strong answer defines stale closure as a callback capturing a variable from an earlier render, demonstrates it with a useEffect interval that logs a stale count because the empty dependency array freezes the closure, and fixes it by including count in dependencies and returning a cleanup function to clear the interval. Red flag: suggesting useRef as a fix without explaining the mutation model, or claiming setState callbacks alone prevent the issue.
Read the original → dmitripavlutin.com
- #react
- #hooks
- #closures
- #useeffect
- #interview
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