Interview Q&A / System Design
System Design interview questions
Caching, scaling, databases and classic design problems for beginners.
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- What does the dependency array do in useEffect?
It tells React when to re-run the effect. No array means after every render, an empty array means once after mount, and a list of values means after renders where one of them changed, compared with Object.is.
BeginnerQuick answer1 min read