JavaScript interview questions: step by step

Easy

1. What is the DOM?
2. What is the “use strict”?
3. How many data types are in js?
4. What is the difference between primitive and non-primitive data types?
5. What is the Symbol data type?
6. What is the BigInt data type?
7. What is the difference between strict equality and loose equality?
8. How many are there ways of creating an Array?
9. How many are there ways of creating Objects?
10. How many are there ways of declaring function?

Medium

1. What is the hoisting?
2. What is the difference between var, let, and const?
3. What is the difference between arrow function and function expression?
4. What is the scope and how many are they?

Hard

1. What is the prototype?
2. What is the difference between prototype and proto?
3. What is the “this (call, apply, bind)”?
4. What is the closure?
5. What is an event loop?
6. What is the callback hell and explain the promise? Promise methods?
7. What is the polyfill in JS?
8. JS classes?
9. Async awaits, try-catch, fetch?
10. What is a proxy?
11. Function generator, symbol iterator, for of, for in?
12. Array methods (forEach, map, reduce, filter)?
13. Map, Set, WeakMap, WeakSet?
14. Spread vs Rest?
15. Object and Array Destruction?
16. Local storage, session storage, cookies, index DB?