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

1. 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

2. 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

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. Which programming language is TypeScript based on?

JavaScript

Java

Python

C++

5. 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

6. 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';

7. 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

8. 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;

9. What is TypeScript primarily used for?

Developing mobile applications

Server-side scripting

Creating responsive web designs

Enhancing JavaScript with static typing

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

array

list

set

collection

12. 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

13. 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

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

Access modifier

Type assertion

Decorator

Mixin

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

boolean

undefined

nullable

any

16. 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

17. 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

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. 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

20. 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

TypeScript MCQ Test 4