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

1. How do you define an optional property in a TypeScript interface?

prop?: type

optional prop: type

prop: type?

prop: optional type

2. What is TypeScript's 'module' system used for?

To define a class

To create a loop

To organize and encapsulate code into reusable units

To print output

3. Which utility type transforms all properties of a type to be read-only?

Partial<Type>

Readonly<Type>

Record<K, T>

Pick<Type, Keys>

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

(1, 2, 3)

[1, 2, 3]

{1, 2, 3}

<1, 2, 3>

5. What is TypeScript's 'generics' feature used for?

To create generic functions and classes that work with multiple data types

To generate random data

To define a class

To print output

6. In TypeScript, how do you define an optional function parameter?

By using 'optional' keyword

By using 'required' keyword

By using a question mark '?'

By using a colon ':'

7. What is the TypeScript feature used to combine multiple types into a single type?

Type casting

Type assertion

Union type

Intersection type

8. 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

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

for...in

for...of

forEach

while

10. 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

11. 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;

12. 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

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

Defining classes

Defining loops

Defining anonymous functions

Defining interfaces

14. What is the primary goal of TypeScript?

To add static typing to JavaScript

To replace JavaScript

To create complex animations

To build mobile apps

15. What is TypeScript's 'class' used for?

To create a new object

To define a loop

To define a blueprint for creating objects with shared properties and methods

To print output

16. 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[]

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

To create a new file

To group related code

To define a class

To declare a variable

18. 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

19. Which TypeScript feature is used to create a new type that is composed of existing types?

Type casting

Type assertion

Union type

Intersection type

20. Which keyword is used to declare a variable in TypeScript with a specific type?

var

let

type

const

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

Enum

Literal Types

Union Types

Type Aliases

22. What is the purpose of the 'unknown' type in TypeScript?

It is used when the type of a variable is not known

It is a safer alternative to the 'any' type

It is used to define variables that have no type

Both A and B

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

print()

log()

console.log()

display()

24. Which keyword is used to declare a variable in TypeScript?

var

let

const

variable

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. Which TypeScript feature allows you to work with a variable that could be of several different types?

Union Types

Intersection Types

Generic Types

Any Types

27. 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

28. In TypeScript, which of the following is the correct way to define an array of numbers?

let numbers: number[];

let numbers: array<number>;

let numbers: Array[number];

let numbers: [number];

29. 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

30. What is the purpose of the 'break' statement in TypeScript?

To continue to the next iteration

To exit a loop or switch statement

To skip a loop iteration

To declare a function

31. Which programming language is TypeScript based on?

JavaScript

Java

Python

C++

32. What is TypeScript's 'type inference'?

A feature that allows automatic conversion of data types

A feature that infers the type of a variable based on its value

A feature that enforces strict typing

A feature that defines custom data types

33. Which keyword is used to declare a constant variable in TypeScript?

let

var

const

readonly

34. 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

35. Which TypeScript keyword is used to indicate that a function doesn't return any value?

none

null

undefined

void

36. Which TypeScript feature is used for ensuring code blocks are never reached?

typeof

never type

undefined type

void type

37. What is TypeScript?

A markup language

A programming language

A database system

A text editor

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

init

create

constructor

initialize

39. Which of the following correctly describes the 'Partial' utility type in TypeScript?

Transforms all properties of a type to be optional

Transforms all properties of a type to be readonly

Creates a type with all properties of another type, excluding some

Extracts a subset of properties from a type

40. 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

41. 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';

42. 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>

43. What is the purpose of TypeScript's 'null' and 'undefined' types?

To represent the absence of a value

To define a class

To create a loop

To print output

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

typeof

instanceof

All of the above

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

func myFunction() {}

function myFunction() {}

method myFunction() {}

def myFunction() {}

46. In TypeScript, how do you declare a variable with a specific type?

let variableName: type = value;

var variableName = value;

variableName type = value;

const variableName = value;

47. 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

48. How do you define a class in TypeScript?

class MyClass {}

create class MyClass {}

new class MyClass {}

type MyClass {}

49. 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

50. 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

TypeScript MCQ Test 1