README

JavaScript Interview Questions & Answers

 Click :star:if you like the project and follow @SudheerJonna for more updates. Coding questions available here. Check DataStructures and Algorithms for DSA related questions and ECMAScript for all ES features.)

---



  
    
  



 Practice 280+ JavaScript coding interview questions in-browser. Built by ex-FAANG interviewers. No AI-generated fluff. No fake reviews. Try GreatFrontEnd → 💡




  
    
  



 I recommend this JavaScript Projects courses and this Advanced JavaScript Course to become top 10% at JS and this coding interview bootcamp to ace your coding interview and actually get hired.

 Table of Contents


| No. | Questions |
| --- | --------- |
| 1 | What are the possible ways to create objects in JavaScript |
| 2 | What is a prototype chain |
| 3 | What is the Difference Between call, apply, and bind |
| 4 | What is JSON and its common operations |
| 5 | What is the purpose of the array slice method |
| 6 | What is the purpose of the array splice method |
| 7 | What is the difference between slice and splice |
| 8 | How do you compare Object and Map |
| 9 | What is the difference between == and === operators |
| 10 | What are lambda expressions or arrow functions |
| 11 | What is a first class function |
| 12 | What is a first order function |
| 13 | What is a higher order function |
| 14 | What is a unary function |
| 15 | What is the currying function |
| 16 | What is a pure function |
| 17 | What are the benefits of pure functions |
| 18 | What is the purpose of the let keyword |
| 19 | What is the difference between let and var |
| 20 | What is the reason to choose the name let as a keyword |
| 21 | How do you redeclare variables in a switch block without an error |
| 22 | What is the Temporal Dead Zone |
| 23 | What is an IIFE (Immediately Invoked Function Expression) |
| 24 | How do you decode or encode a URL in JavaScript? |
| 25 | What is memoization |
| 26 | What is Hoisting |
| 27 | What are classes in ES6 |
| 28 | What are closures |
| 29 | What are modules |
| 30 | Why do you need modules |
| 31 | What is scope in javascript |
| 32 | What is a service worker |
| 33 | How do you manipulate DOM using a service worker |
| 34 | How do you reuse information across service worker restarts |
| 35 | What is IndexedDB |
| 36 | What is web storage |
| 37 | What is a post message |
| 38 | What is a Cookie |
| 39 | Why do you need a Cookie |
| 40 | What are the options in a cookie |
| 41 | How do you delete a cookie |
| 42 | What are the differences between cookie, local storage and session storage |
| 43 | What is the main difference between localStorage and sessionStorage |
| 44 | How do you access web storage |
| 45 | What are the methods available on session storage |
| 46 | What is a storage event and its event handler |
| 47 | Why do you need web storage |
| 48 | How do you check web storage browser support |
| 49 | How do you check web workers browser support |
| 50 | Give an example