JavaScript Datatypes and Variables

1.		Which of the following is not a primitive data type in JavaScript?

Number

String

Object

Boolean

2.		Which of the following is a valid way to declare a variable with constant block scope in JavaScript?

var myConst;

let myConst;

const myConst;

Only A and B

3.		Which of the following is not a valid data type in JavaScript?

Undefined

Null

NaN

Char

4.		Which of the following is a valid way to declare and initialize a number variable in JavaScript?

var myNum = 42;

let myNum = 3.14;

const myNum = -99;

All of the above

5.		What is the result of the following code snippet: typeof undefined;

Undefined

null

undefined

None of the above

6.		What is the data type of a variable that stores an object in JavaScript?

Object

Array

Dictionary

Set

7.		Which of the following is not a valid way to compare two values in JavaScript?

==

===

<=>

!=

8.		What is the data type of a variable that stores a null value in JavaScript?

Object

Null

Undefined

Number

9.		Which of the following is a valid way to concatenate two strings in JavaScript?

Hello + "world";

Hello.concat("world");

Both A and B

None of the above

10.		Which of the following is a valid way to declare an empty array in JavaScript?

var myArr = [];

let myArr = {};

const myArr = ();

All of the above