Excellent Typescript Test - 87+ MCQs: TypeScript test: Evaluate Your Programming Skills with TypeScript Questions and Answers

1. What is the use of the 'this' parameter in TypeScript functions?

To refer to the current class instance

To explicitly specify the type of 'this' within a function

To declare a new variable

To refer to the global scope

2. How can you create a custom type guard in TypeScript?

Using 'typeof' operator

Using 'instanceof' operator

By defining a function that returns a boolean

By using the 'in' keyword

3. What is the use of the 'declare' keyword in TypeScript?

To define a new variable

To declare the type of a variable without initializing it

To declare a dependency

To declare a new function

4. What is the purpose of TypeScript's 'as' keyword?

To compare two values

To cast or convert types

To define a variable

To create a class

5. What is the TypeScript equivalent of JavaScript's 'for...in' loop?

for...in

for...of

forEach

while

6. In TypeScript, how do you define a tuple?

(1, 2, 3)

[1, 2, 3]

{1, 2, 3}

<1, 2, 3>

7. What is the purpose of TypeScript's 'import' statement?

To export a module

To import a module or module member

To create a new file

To define a class

8. What TypeScript feature allows for specifying an exact set of string values for a type?

Enum

Literal Types

Union Types

Type Aliases

9. What is the purpose of the 'interface' keyword in TypeScript?

To define a new class

To declare a function

To create a contract for object structure

To import external libraries

10. What is the purpose of TypeScript's 'interface'?

To define a class

To create a new object

To declare the type of an object

To write comments

11. What is a discriminated union in TypeScript?

A union type that includes discriminant properties

A union type that excludes certain types

A special type of intersection type

A union type that is discriminated by the compiler

12. In TypeScript, what is the 'this' keyword used for?

To define a class

To create a loop

To refer to the current instance of an object within a method

To print output

13. What is TypeScript?

A markup language

A programming language

A database system

A text editor

14. What is the TypeScript convention for naming classes?

CamelCase

snake_case

kebab-case

PascalCase

15. In TypeScript, what is the 'any' type used for?

To define a class

To create a loop

To represent a variable with an unknown or dynamic type

To print output

16. Which TypeScript feature is used to describe the shape of an object, including its properties and their types?

Interface

Type assertion

Decorator

Mixin

17. Which operator is used to specify a type guard in TypeScript?

typeof

instanceof

All of the above

18. What is the purpose of TypeScript's 'class' keyword?

To declare a new function

To create an instance of a class

To define a new data type

To define a blueprint for creating objects

19. What does the 'is' keyword do in a TypeScript type predicate?

Checks if a type is assignable to another

Defines a custom type guard

Specifies an inheritance relationship

Creates a conditional type

20. Which TypeScript keyword is used to declare a constant?

var

let

const

variable

21. Which of the following allows TypeScript to infer the return type of a function?

Type Inference

Explicit Typing

Type Assertion

Dynamic Typing

22. How do you define a function in TypeScript?

function functionName() {}

const functionName = () => {}

def functionName() {}

method functionName() {}

23. Which TypeScript feature is used to make a property or method in a class inaccessible from outside the class?

Access modifier

Decorator

Mixin

Type assertion

24. Which data type represents a collection of values in TypeScript?

Object

Array

Tuple

Enum

25. In TypeScript, what is the purpose of the 'namespace' keyword?

To define a class

To create a loop

To group related code into a named container

To print output

26. What is TypeScript's 'tuple' data type used for?

To define a class

To create a loop

To represent an array with a fixed number of elements of different data types

To print output

27. What is the purpose of the 'extends' keyword in generic constraints in TypeScript?

To inherit from another class

To limit the types that can be used with a generic type

To expand a generic type with additional properties

To check if a property exists in an object

28. Which of the following is a valid way to define a string variable in TypeScript?

string name = 'John';

let name: string = 'John';

const name = 'John';

name = 'John';

29. In TypeScript, what is the purpose of the 'try/catch' statement?

To define a class

To create a loop

To handle exceptions and errors

To print output

30. What is the purpose of TypeScript's 'typeof' operator?

To check the type of an expression

To declare a variable

To create an object

To define a function

TypeScript MCQ Test 3