JavaScript Essentials Quiz

Which of these is not correct about variables?

• Variables are fundamental to programming

• Variables give names to data

• Variables are containers used to store data or data values

• Variables are the data types used in JavaScript

Which of these is not a primitive data type?

• String

• Number

• Array

• Undefined

What data type is the following variable?
const PI = 3.14;

• String

• Constant

• Number

• Bigint

What data type is the following variable?
c = 85;

• Constant

• String

• Number

• Boolean

Which one is generally better for an unknown variable, line 1 or line 2?
let empty1 = undefined; //line 1
let empty2 = null; //line 2

• Line 1

• Line 2

What is the console output for the following code?
let greetStr1 = "Hello";

greetStr1 = "World";

console.log(greetStr1);

• Hello

• World

• HelloWorld

• Hello World

What will be logged to the console?

let x = "World!";

let y = "Hello $(x)";

console.log(y);

• Hello

• World

• Hello World!

• HelloWorld

let a = "Hello";

a = prompt("World");

console.log(a)

• Hello

• World

• HelloWorld

• What ever the user enters in

What will be the value of b output to the console?

let a = 5;

let b = 70;

let c = "5";

b++;

console.log(b);

• 70

• 5

• 71

• 6

What is the value of result?
let result = 3 + 4 * 2 / 8;

• 1

• 2

• 8

• 4