React Junior Developer Mock Test

Q: What is this reactjs mock test?

This is a comprehensive reactjs mock test with 15 questions covering Core Concepts, Hooks, Data Flow. It simulates real technical interviews with timed conditions and provides detailed explanations.

Q: How long does the test take?

The test has a time limit of 60 minutes. You can pause and resume, but we recommend completing it in one sitting.

Q: Will I get feedback on my answers?

Yes! After each question, you receive immediate feedback with detailed explanations. At the end, you get a comprehensive report showing your strengths and areas for improvement.

Q: Is this test suitable for FAANG interview preparation?

Absolutely! Our questions are curated by FAANG interviewers and cover the exact topics and difficulty levels you'll encounter in top tech company interviews.

Question 1

What is the primary purpose of the Virtual DOM in React?

Answer

To provide a blueprint for the UI that minimizes expensive DOM updates

Question 2

Which hook is used to handle side effects like API calls or subscriptions?

Answer

useEffect

Question 3

How do you pass data from a parent component to a child component?

Answer

Using Props

Question 4

What will happen if you update a component's state directly (e.g., `this.state.count = 1`)?

Answer

The component will not re-render

Question 5

In JSX, how do you embed a JavaScript expression?

Answer

Using { }

Question 6

What is the 'key' prop used for when rendering a list of elements?

Answer

To help React identify which items have changed, been added, or removed

Question 7

Which of the following is a 'Rule of Hooks'?

Answer

Hooks must only be called at the top level of a functional component

Question 8

What does the `useState` hook return?

Answer

An array containing the current state and a setter function

Question 9

How can you prevent a default action (like a form submission) in a React event handler?

Answer

event.preventDefault()

Question 10

What is a 'Fragment' in React?

Answer

A way to group multiple elements without adding extra nodes to the DOM

React Junior Developer Mock Test

Difficulty

Topics Covered

What You'll Get