React Hooks Deep Dive

Master React hooks with questions on useState, useEffect, useContext, useMemo, useCallback, and custom hooks. Covers common pitfalls and best practices.

MEDIUM7 questions12 minProgramming

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1.What happens when you call setState inside useEffect without a dependency array?

It causes an infinite re-render loop

It only runs once on mount

It throws a compile-time error

React batches the updates and runs only once

MEDIUMMultiple Choice

2.What is the primary purpose of the useEffect cleanup function?

To clean up side effects like subscriptions and timers when the component unmounts or before re-running the effect

To reset the component's state to its initial value

To clear the browser cache when navigating away

To remove the component from the DOM manually

MEDIUMMultiple Choice

3.What is the difference between useMemo and useCallback?

useMemo memoizes a computed value; useCallback memoizes a function reference

useMemo is for synchronous operations; useCallback is for async operations

They are identical and interchangeable

useCallback runs the function immediately; useMemo defers execution

MEDIUMMultiple Choice

+ 4 more questions included in the full template