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What is the difference between undefined and not defined in JavaScript?
2
What is a "closure" in JavaScript?
3
What will be the output of the code below?
var trees = ["pine","apple","oak","maple","cherry"];
delete trees[3];
console.log(trees.length);
var trees = ["pine","apple","oak","maple","cherry"];
delete trees[3];
console.log(trees.length);4
What is the difference between == and ===?
5
What does the isNaN() function do?
6
What is the result of "10"+20+30 in JavaScript?
7
How does Array() differ from [] while creating a JavaScript array?
8
What is the difference between declaring a function in the two formats below?var foo = function() {/* Some code */};
function bar() {/* Some code */};
var foo = function() {/* Some code */};function bar() {/* Some code */};9
What is Scope in JavaScript?
10
How to call other class methods?
11
Explain the difference between class inheritance and prototypal inheritance.
12
What is prototype property in JavaScript?
13
What is the reason for wrapping the entire content of a JavaScript source file in a function block?
14
Why would you use use strict at the beginning of a JavaScript source file?
15
What is the difference between a method and a function in javascript?
16
What is JavaScript self-invoking anonymous function?
17
What will the code below output?var a = [1, 2, 3];
a[10] = 99;
console.log(a[6]);
var a = [1, 2, 3];
a[10] = 99;
console.log(a[6]);18
What will be the output of the following code?var Employee = {company: 'Acme'}
var employee1 = Object.create(Employee);
delete employee1.company
console.log(employee1.company);
var Employee = {company: 'Acme'}
var employee1 = Object.create(Employee);
delete employee1.company
console.log(employee1.company);19
What will be the output of the following code?var z = 1, y = z = typeof y;
console.log(y);
var z = 1, y = z = typeof y;
console.log(y);20
Consider the two functions below. Will they both return the same thing?function foo1(){return {bar: "hello"};}function foo2(){return{bar: "hello"};}
function foo1(){return {bar: "hello"};}function foo2(){return{bar: "hello"};}Join 5K+ tech leaders
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