💼 Zepto Frontend Engineer Interview Experience — 40LPA

Overview

The candidate, having accrued significant experience at CARS24, sought new opportunities and was drawn to Zepto's scale and frontend challenges. The Zepto interview process was described as sharp and focused, emphasizing hands-on problem-solving and a deep understanding of ReactJS and JavaScript.

Interview Rounds

The interview process consisted of two primary rounds:

Round 1: Problem Solving + JavaScript + React Fundamentals

This round assessed the candidate's theoretical knowledge, logical reasoning, and ability to apply concepts to real-world scenarios. Questions included:

1. Performance-Based Web Questions:

   • How SSR helps in performance.
   • Bundle splitting and lazy loading.
   • Methods to reduce TTI (Time to Interactive).

2. Breadcrumb Chain Problem (Tree Traversal):

   Given a breadcrumb array, generate the complete hierarchy starting from the root.

   const breadCrum = [
     { id: 3, parentId: 12, title: "Headphones" },
     { id: 19, parentId: 28, title: "True wireless" },
     { id: 28, parentId: 3, title: "Wired" },
     { id: 12, parentId: null, title: "Audio" },
     { id: null, parentId: 19, title: "Bluetooth" }
   ];
   

   Expected Output:

   Audio >> Headphones >> Wired >> True wireless >> Bluetooth
   

   The suggested approach involved a recursive or iterative path-building mechanism with a Map of id → node.

3. Output of setTimeout and setInterval:

   Questions focused on:

   • How JavaScript timers work.
   • Event loop and call stack behavior.
   • Order of execution in asynchronous code.

4. useMemo() vs useCallback():

   // useMemo - Caches a computed value
   const memoizedValue = useMemo(() => computeExpensiveValue(a, b), [a, b]);
   // useCallback - Caches a function reference
   const memoizedCallback = useCallback(() => handleSubmit(data), [data]);
   

   useCallback is used for function identity, particularly when passing functions to child components. useMemo is for caching results of expensive computations.

5. Programmatically Add Event Listener: