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

1. 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

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

Enum

Literal Types

Union Types

Type Aliases

3. What does the 'keyof' keyword do in TypeScript?

Returns the values of an object

Returns the keys of an object as a union type

Creates a new object

Checks the presence of a key in an object

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 feature used to combine multiple types into a single type?

Type casting

Type assertion

Union type

Intersection type

6. What is TypeScript's 'namespace' used for?

To create a new file

To group related code

To define a class

To declare a variable

7. What is TypeScript's 'export' keyword used for?

To import a module

To define a class

To export a module or module member

To declare a variable

8. Which data type is used to represent a collection of values in TypeScript?

array

list

set

collection

9. Which of the following is the correct way to define an interface for a function in TypeScript?

interface ExampleFunction { (param1: type1, param2: type2): returnType }

interface ExampleFunction { function(param1: type1, param2: type2): returnType }

function ExampleFunction(param1: type1, param2: type2): returnType;

type ExampleFunction = (param1: type1, param2: type2) => returnType;

10. What is the TypeScript equivalent of JavaScript's 'constructor' function?

init

create

constructor

initialize

11. 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';

12. In TypeScript, how do you define a function?

func myFunction() {}

function myFunction() {}

method myFunction() {}

def myFunction() {}

13. 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

14. What is the purpose of namespaces in TypeScript?

To bundle related interfaces and classes

To create a new module

To define a new scope for variables

To import external libraries

15. Which TypeScript data type is used for variables that may have a 'null' or 'undefined' value?

boolean

undefined

nullable

any

16. What is the TypeScript equivalent of 'console.log()' in JavaScript?

print()

log()

console.log()

display()

17. In TypeScript, what is the difference between 'interface' and 'type' when defining a new type?

Interfaces are only for objects, while types can be used for primitives too

Types can be used for unions and intersections, interfaces cannot

Interfaces can be merged, but types cannot

All of the above

18. 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

19. What is the TypeScript equivalent of 'undefined' in JavaScript?

null

undefined

void

nil

20. What is the purpose of TypeScript's 'enum'?

To define a class

To create a new object

To define a set of named constants

To print output

21. In TypeScript, what is the purpose of the 'import' statement?

To define a class

To create a loop

To include external modules or dependencies

To print output

22. Which TypeScript feature is used to apply metadata to classes, methods, or properties?

Access modifier

Type assertion

Decorator

Mixin

23. What is TypeScript's 'arrow function' syntax used for?

Defining classes

Defining loops

Defining anonymous functions

Defining interfaces

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

Object

Array

Tuple

Enum

25. 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

26. 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

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

typeof

instanceof

All of the above

28. How do you declare a readonly array in TypeScript?

let readonlyArray: ReadonlyArray<number>

let readonlyArray: number[] readonly

readonly let readonlyArray: number[]

let readonlyArray: const number[]

29. 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

30. Which utility type constructs a type by picking the set of properties 'K' from 'T'?

Pick<T, K>

Omit<T, K>

Partial<T>

Exclude<T, U>

TypeScript MCQ Test 3