Front-End Interview Questions

General knoweldge of Front-End development and behavioral questions.

tag: Library tag: JavaScript

2. What is Prototypal Inheritance? How does it work?JavaScript
3. explain `this` keyword in JavaScript JavaScript
4. what is Closure and how does it work?JavaScript
5.`var` vs `let` vs `const`JavaScript
6. Explain the concept of Promise to a 5-year-old JavaScript
7. Map vs Object vs Set vs Array JavaScript
8. difference between `==` and `===`JavaScript
14. Explain the differences between AMD, CommonJS and ES modules JavaScript
15. `Array.prototype.forEach()` vs `Array.prototype.map()`JavaScript
16. How does `instanceOf` work? difference with `typeof`JavaScript
17. Explain `new` operator in JavaScript. What exactly does it do?JavaScript
18. Explain `macrotask` and `microtask`JavaScript
29. What is the difference between Express and Koa JavaScript Library
32. Explain `async` and `await`JavaScript
44. How Garbage collection in JavaScript works?JavaScript
45. What is memory leak ? How to debug and prevent it?JavaScript
46. Explain Event Loop in Browser and in Node.js JavaScript
47. What is Virtual DOM? How does it work?JavaScript
48. What is HOC(Higher Order Component)?JavaScript React
51. What is SSR? What is the pros and cons?JavaScript
53. What are WeakSet and WeakMap?JavaScript
59. What is Array-Like Objects in JavaScript?JavaScript
60. When do we need to use non-strict mode?JavaScript
61. How to publish an NPM package JavaScript
62. What is Promise ? How to resolve a bunch of Promises in order?JavaScript
63. What is Factory Pattern?JavaScript
64. What is the difference between ES6 Class and ES5 implementation?JavaScript
65. What is Decorator Pattern JavaScript
67. What is the difference between setTimeout and setInterval?JavaScript
69. What is Proxy Pattern?JavaScript
70. What is Observer Pattern?JavaScript
76. What is the difference between for...in and Object.keys?JavaScript
77. What is difference between `for ... of` and `forEach`JavaScript
116. What is Singleton Pattern?JavaScript
117. What is JWT(JSON Web Token)?JavaScript
130. What is the difference between modules and standard scripts?JavaScript
134. is Array.prototype.sort() stable in JavaScript?JavaScript
141. What does Object.freeze() do?JavaScript
146. what is 'use strict' for?JavaScript
152. What is Generator and what is it useful for?JavaScript
153. why 0.1 + 0.2 !== 0.3 ? How to deal with float precision in your apps?JavaScript
154. How would you add offline support to your web app?JavaScript
161. explain iterators and generators JavaScript
162. What is the difference between function declaration and function expression?JavaScript
164. What is the difference between `null` and `undefined` ? Which one should I use?JavaScript