Javascript Interview Questions with answers

If you are looking forward to crack JavaScript interviews with ease , then you are at the right place.

JavaScript is a very tricky language and JavaScript interviews becomes more tricky.

Working in Javascript and cracking Javascript interviews are two different things.

This course focuses on revising most asked interview questions around JavaScript.  Interview is all about expressing your answers in a precise and proper way. You can have tons of knowledge , you must have done tons of coding but cracking interview is a different ball game.

This course is revision course where we have focused on what kind of questions are asked and how to answer them in a elaborate way.

Below is the complete course agenda.

Happy learning , Happy job hunting.

JavaScript basics Interview questions with answers.

• Question 1 :- Why do we call JavaScript as dynamic language

• Question 2 :- how does JavaScript determine data types ?

• Question 3 :- What is typeof ?

• Question 4 :- How to check data type in JavaScript ?

• Question 5 :- What are different datatypes in JavaScript ?

• Question 6 :- Explain Undefined Data types ?

• Question 7 :- What is Null ?

• Question 8 :- Differentiate between Null and Undefined ?

• Question 9 :- Explain Hoisting ?

• Question 10 :- Are JavaScript initialization hoisted ?

• Question 11 :- What are global variables ?

• Question 12 :- What are the issues with Global variables ?

• Question 13 :- What happens when you declare variable with out VAR ?

• Question 14 :- What is Use Strict ?

• Question 15 :- How to force developers to use Var keyword ?

• Question 16 :- How can we handle Global Variables ?

• Question 17 :- How can we avoid Global variables ?

• Question 18 :- What are Closures ?

• Question 19 :- Why do we need Closures ?

• Question 20 :- Explain IIFE ?

• Question 21 :- What is the use of IIFE ?

• Question 22 :- What is name collision in global scope ?

• Question 23 :- IIFE vs Normal Function

• Question 24 :- What are design patterns ?

• Question 25 :- Which is the most used design pattern

• Question 26 :- What is module Pattern and revealing module pattern ?

• Question 27 :- How man ways are there to create JavaScript objects ?

• Question 28 :- How can we do inheritance in JavaScript ?

• Question 29 :- What is prototype in JavaScript ?

• Question 30 :-Explain Prototype chaining ?

• Question 31 :- What is Let Keyword ?

• Question 32 :- Are Let variables hoisted ?

• Question 33 :- Explain Temporal Dead Zone ?

• Question 34 :- Let vs Var

• Question 35 :- String Concatenation and Arithmetic puzzle

7 Important JavaScript Interview Questions on ES6 & JavaScript Functions.

• Question 36 :- What is class in ES6 ?

• Question 37 :- So with class Keyword does it imply JavaScript is a OOP language ?

• Question 38 :- Differentiate between class and normal function ?

• Question 39 :- What is a Arrow function ?

• Question 40 :- Why do we use Arrow function ?

• Question 41 :- Differentiate between Arrow vs Normal Function ?

• Question 42 :- Does Arrow function create its own this ?

Technical Questions on Sync, Async, Threading, Event Loop, Blocking and Non-Blocking and Callback Queue.

• Question 43. Explain Synchronous execution ?

• Question 44. What is a call Stack ?

• Question 45. What is a blocking call ?

• Question 46. How to avoid blocking calls ?

• Question 47. Explain Asynchronous execution ?

• Question 48. Synch vs Asynch ?

• Question 49. How can we do Asynch calls ?

• Question 50. What is a thread ?

• Question 51. Explain Multi-threading ?

• Question 52. Is JavaScript Multi-threaded ?

• Question 53. Then how does Settimeout run ?

• Question 54. What is a WebAPI/Browser API ?

• Question 55. What is a Event loop and callback queue?

• Question 56. Eventloop and Callback code question

JavaScript Promises, Chaining, callbacks, Asynch, Await, Micro,Macro, Webworker.

• 57. What are promises in JavaScript?

• 58. How to catch error in promises ?

• 59. What are callbacks ?

• 60. Explain Promise chaining ?

• 61. Three States of Promises ?

• 62. Explain Async and Await ?

• 63. Why to make a promise synch?

• 64. Does Async represent a promise ?

• 65. Can we use Async with out Await ?

• 66. What are Micro and Macro queues ?

• 67. Who executes first Micro or Macro ?

• 68. How will the code execute(testing Micro and Macro)?

• 69. Can we schedule a MicroTask Manually ?

• 70. Are Micro and Macro Task synch or Async ?

• 71. Explain Webworker ?

• 72. How to create WebWorker ?

• 73. What are postmessage and onmessage in webworker ?

• 74. Can Webworker update UI ?

• 75. WebWorker vs Async Task

• 76. WebWorker vs Promises

• 77. Asynch vs Threads

• 78. Concurrency vs Parallelism