JavaScript Hoisting and Scope Quiz

By Areeb Anwar / September 28, 2024

Test your knowledge of JavaScript Hoisting and Scope with this interactive quiz! Learn the key differences between var, let, and const, understand function hoisting, and master variable scope in JavaScript.

1 / 15

What happens if you declare a var variable inside a block (e.g., within an if statement)?

It is scoped to the block

It is function-scoped or globally scoped

It throws an error

2 / 15

Which of the following is NOT a valid use of let?

Declaring a block-scoped variable

Reassigning a value to an existing let variable

Redeclaring a let variable in the same scope

3 / 15

How does function hoisting work in JavaScript?

Only function expressions are hoisted

Both function declarations and function expressions are hoisted

Function declarations are hoisted, but function expressions are not

4 / 15

Which of the following is true for variables declared with var?

They are not hoisted

They are block-scoped

They can be updated and re-declared

5 / 15

What type of error occurs when trying to reassign a const variable?

SyntaxError

ReferenceError

TypeError

6 / 15

In which scenario would you get a ReferenceError due to hoisting?

When accessing a var variable before declaration

When accessing a let or const variable before declaration

When declaring a variable without initializing it

7 / 15

Which keyword should be used for declaring a constant variable that cannot be reassigned?

var

let

const

8 / 15

What is the behavior of const when hoisted?

It is initialized with undefined b) c)

It exists in a Temporal Dead Zone (TDZ) until initialization

It can be accessed before declaration

9 / 15

Which of the following variables is block-scoped?

var

let

Both var and let

10 / 15

What value is assigned to a var variable before initialization?

null

undefined

Throws an error

11 / 15

Where is a function-scoped variable accessible?

Only within the function where it’s declared

Throughout the entire code

Within the block where it’s declared

12 / 15

Which scope allows variables to be accessible everywhere in the code?

Block scope

Function scope

Global scope

13 / 15

What happens when you try to access a let variable before declaration?

Returns undefined

Throws a ReferenceError

Automatically assigns the value null

14 / 15

Which of the following is true about var in JavaScript?

var is block-scoped

var can be redeclared in the same scope

var is not hoisted

15 / 15

What is hoisting in JavaScript?

Moving function and variable declarations to the top of their scope

Moving only variable values to the top of their scope

Hoisting only applies to let and const

Your score is

The average score is 76%

Read Before Attempting Quiz:

Do You Know Hoisting in JavaScript? Discover the Secrets of Variable Scope

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