• Courses
  • Tutorials
  • DSA
  • Data Science
  • Web Tech
Switch to Dark Mode

Variables and Data Types in TypeScript

This quiz will cover the topics related to variables and data types in TypeScript.

Last Updated : Feb 11, 2025
Discuss
Comments

Question 1

Which keyword is used to declare a variable with block scope in TypeScript?

  • A

    var

  • B

    let

  • C

    const

  • D

    Both b and c

Discuss it

Question 2

Which keyword is used to declare a variable with block scope in TypeScript?

  • A

    let allows reassignment, but const does not

  • B

    const allows reassignment, but let does not

  • C

    Both allow reassignment

  • D

    There is no difference

Discuss it

Question 3

What will be the output of the following code?

TypeScript 
let a = 10;
a = "Hello";
console.log(a);


  • A

    Hello

  • B

    10

  • C

    Compilation error

  • D

    Undefined

Discuss it

Question 4

Which data type is NOT available in TypeScript?

  • A

    number

  • B

    boolean

  • C

    character

  • D

    undefined

Discuss it

Question 5

What does typeof null return in TypeScript?

  • A

    "null"

  • B

    "object"

  • C

    "undefined"

  • D

    "string"

Discuss it

Question 6

What is the any type used for in TypeScript?

  • A

    To allow variables to hold any type of value

  • B

    To restrict a variable to a single type

  • C

    To enforce strict type checking

  • D

    To define a variable without assigning a value

Discuss it

Question 7

What is the default type of a variable declared without an explicit type in TypeScript?

  • A

    any

  • B

    unknown

  • C

    string

  • D

    void

Discuss it

Question 8

What will be the output of the following code?

TypeScript 
let x: unknown = "Hello";
console.log(x.length);


  • A

    5

  • B

    undefined

  • C

    Compilation error

  • D

    Runtime error

Discuss it

Question 9

Which type allows a variable to store either a number or a string?

  • A

    mixed

  • B

    any

  • C

    union

  • D

    multi

Discuss it

Question 10

What does the readonly modifier do in TypeScript?

  • A

    Prevents reassignment of a variable

  • B

    Prevents modification of a property after initialization

  • C

    Prevents a variable from being accessed

  • D

    Makes a variable null by default

Discuss it

Ready to go from coding beginner to development pro? Our DSA to Development Coding Guide has everything you need to crush coding interviews and ace real-world projects! Limited spots available!
Enroll Now and Transform Your Coding Skills! Also get 90% fee refund on completing 90% of the course in 90 days! Take the Three 90 Challenge today.

There are 10 questions to complete.

Take a part in the ongoing discussion