My SDE-2 Frontend Interview Experience at Cars24

Overview

This document details the interview experience of a candidate for a Frontend SDE-2 position at Cars24. The interview process was structured around assessing the candidate's proficiency in JavaScript, React, and general problem-solving abilities, with a particular emphasis on frontend performance.

Interview Rounds

The interview process comprised three distinct rounds:

Round 1: Core JavaScript Concepts

This round focused on evaluating the candidate's foundational knowledge of JavaScript. The interviewer explored the candidate's understanding of the following concepts:

• Hoisting
• Closures
• Currying
• The this keyword
• Prototype inheritance
• Promises

The candidate reportedly answered all questions confidently, demonstrating a strong grasp of JavaScript fundamentals.

Round 2: React Coding Challenges

The second round involved solving practical coding problems using React. The candidate was presented with the following challenges:

• Progress Bar Component: The candidate implemented a dynamic progress bar component that updated based on user input. The interviewer assessed the candidate's approach to the problem, code modularity, and overall code quality.
• Job Board Application: The candidate developed a job board interface with filtering and rendering capabilities. The solution required effective state management and UI rendering.

The candidate successfully completed both challenges and received positive feedback on the solutions provided.

Round 3: Techno HM Round (1.5 hours)

The final round combined technical problem-solving with high-level discussions on performance optimization. The candidate faced the following challenges:

• Custom Hook for useEffect: The candidate was tasked with creating a custom React Hook to encapsulate logic typically found within useEffect. The hook was designed to be reusable and handle dependencies effectively.
• Grid Lights Problem: The candidate implemented a solution for toggling grid lights based on specific conditions, emphasizing the creation of an interactive UI with clean, readable code.
• Snake and Ladder Game: The candidate built a simplified Snake and Ladder game with the following rules:
  • Two players start at position 0.
  • A dice roll determines the player's next move.
  • The game concludes when a player reaches position 100.

The candidate implemented the necessary logic for dice rolls, player movements, and win condition handling.

Beyond the coding challenges, the discussion shifted to performance optimization, covering areas such as:

• Network performance
• Rendering performance
• JavaScript performance optimization techniques

The candidate reported struggling to provide in-depth answers regarding performance optimization, citing limited knowledge in this area.

Key Takeaways

Although the candidate successfully solved the coding challenges presented, they were not selected for the role. The candidate believes that a limited understanding of performance optimization techniques may have contributed to the final decision.

For individuals preparing for an SDE-2 role at Cars24, it is recommended to thoroughly review:

• JavaScript fundamentals
• React coding best practices
• Performance optimization (networking, rendering, and JavaScript performance)