Question 1

Explain React's reconciliation algorithm. How does the virtual DOM diffing work and what are its key assumptions?

Accepted Answer

This is a hard-difficulty React interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 2

What is React Fiber? Why was it introduced and what problems does it solve over the old stack reconciler?

Accepted Answer

This is a hard-difficulty React interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 3

What is the difference between useEffect and useLayoutEffect? Give a concrete example where using the wrong one causes a bug.

Accepted Answer

This is a medium-difficulty React interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 4

You have a component that re-renders 60 times per second during scroll. Walk through your optimization strategy.

Accepted Answer

This is a hard-difficulty React interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 5

Explain the rules of hooks. Why does React enforce them and what breaks if you violate them?

Accepted Answer

This is a medium-difficulty React interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 6

Compare React Context API vs Redux for state management. When does Context become a performance problem?

Accepted Answer

This is a medium-difficulty React interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 7

What are React Server Components? How do they differ from SSR and when should you reach for them?

Accepted Answer

This is a hard-difficulty React interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 8

Explain the difference between controlled and uncontrolled components. What are the tradeoffs?

Accepted Answer

This is a easy-difficulty React interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

React Interview Questions

Interview Questions

Explain React's reconciliation algorithm. How does the virtual DOM diffing work and what are its key assumptions?

What is React Fiber? Why was it introduced and what problems does it solve over the old stack reconciler?

What is the difference between useEffect and useLayoutEffect? Give a concrete example where using the wrong one causes a bug.

You have a component that re-renders 60 times per second during scroll. Walk through your optimization strategy.

Explain the rules of hooks. Why does React enforce them and what breaks if you violate them?

Compare React Context API vs Redux for state management. When does Context become a performance problem?

What are React Server Components? How do they differ from SSR and when should you reach for them?

Explain the difference between controlled and uncontrolled components. What are the tradeoffs?