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

1. What is the TypeScript convention for naming variables?

CamelCase

snake_case

kebab-case

PascalCase

2. 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

3. 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

4. What is TypeScript's 'type alias' used for?

To define a class

To create a new object

To create a custom name for a data type

To print output

5. What does the 'as' keyword do in TypeScript?

Type casting

Variable declaration

Function invocation

Type checking

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

func myFunction() {}

function myFunction() {}

method myFunction() {}

def myFunction() {}

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

for...in

for...of

forEach

while

8. 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

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

Partial<Type>

Readonly<Type>

Record<K, T>

Pick<Type, Keys>

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

Access modifier

Type assertion

Decorator

Mixin

11. 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

12. What is TypeScript's equivalent of JavaScript's 'null'?

undefined

void

null

nil

13. 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

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

prop?: type

optional prop: type

prop: type?

prop: optional type

15. What is TypeScript primarily used for?

Developing mobile applications

Server-side scripting

Creating responsive web designs

Enhancing JavaScript with static typing

16. 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';

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

(1, 2, 3)

[1, 2, 3]

{1, 2, 3}

<1, 2, 3>

18. 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

19. 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

20. 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;

21. 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

22. 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

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

Interface

Type assertion

Decorator

Mixin

24. How do you define a tuple type in TypeScript?

[type1, type2]

{type1, type2}

(type1, type2)

type1 | type2

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

typeof

never type

undefined type

void type

27. 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

28. What is the primary goal of TypeScript?

To add static typing to JavaScript

To replace JavaScript

To create complex animations

To build mobile apps

29. In TypeScript, what is the purpose of the 'as' keyword?

To define a class

To cast one type into another

To create a loop

To print output

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

let

var

const

readonly

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

null

undefined

void

nil

32. 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

33. Which programming language is TypeScript based on?

JavaScript

Java

Python

C++

34. 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

35. What is the correct way to annotate a function return type in TypeScript?

function example(): returnType

function example() -> returnType

returnType function example()

function example() returns returnType

36. 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

37. How can you declare a variable that can either be a number or a null in TypeScript?

let variable: number | null;

let variable: number & null;

let variable: null[number];

let variable: number = null;

38. 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

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

To create a new file

To group related code

To define a class

To declare a variable

40. 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

41. 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

42. 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

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

var

let

const

variable

44. 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

45. 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

46. 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

47. 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 ':'

48. 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

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

Type casting

Type assertion

Union type

Intersection type

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

var

let

const

variable

TypeScript MCQ Test 1