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

1. 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

2. What is the TypeScript convention for naming variables?

CamelCase

snake_case

kebab-case

PascalCase

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

Object

Array

Tuple

Enum

4. 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

5. 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;

6. What is the purpose of the 'extends' keyword in TypeScript?

To create a new class

To declare a variable

To extend the functionality of a class

To define a function

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

var

let

const

variable

8. 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;

9. 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

10. 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

11. 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

12. 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

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

null

undefined

void

nil

14. 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

15. 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

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

(1, 2, 3)

[1, 2, 3]

{1, 2, 3}

<1, 2, 3>

17. 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

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

prop?: type

optional prop: type

prop: type?

prop: optional type

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

let

var

const

readonly

21. 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

22. 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 ':'

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

print()

log()

console.log()

display()

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

none

null

undefined

void

25. 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

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

Type casting

Variable declaration

Function invocation

Type checking

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

Access modifier

Type assertion

Decorator

Mixin

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

Interface

Type assertion

Decorator

Mixin

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

typeof

instanceof

All of the above

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

[type1, type2]

{type1, type2}

(type1, type2)

type1 | type2

31. What is TypeScript's 'async/await' feature used for?

To define a class

To create a loop

To work with asynchronous operations and promises

To print output

32. 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

33. 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

34. 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

35. 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

36. 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>

37. 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

38. 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[]

39. 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

40. 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

TypeScript MCQ Test 2