TypeScript MCQ (Multiple Choice Questions) With Answers, TypeScript Online Quiz

1 .

TypeScript is a ?

A)

strongly typed

B)

object oriented

C)

compiled language

D)

All of the above

Correct Answer : All of the above

Explanation : TypeScript is a strongly typed, object oriented, compiled language. It was designed by Anders Hejlsberg (designer of C#) at Microsoft.

2 .

Who developed TypeScript language?

A)

Apple

B)

IBM

C)

Microsoft

D)

Google

Correct Answer : Microsoft

Explanation :

TypeScript is a programming language developed and maintained by Microsoft Technical Fellow Steve Lucco. It is a strict syntactical superset of JavaScript and adds optional static typing to the language. It is designed for the development of large applications and transpiles to JavaScript. As it is a superset of JavaScript, existing JavaScript programs are also valid TypeScript programs.

TypeScript may be used to develop JavaScript applications for both client-side and server-side execution (as with Node.js or Deno). Multiple options are available for transpilation. The default TypeScript Compiler can be used, or the Babel compiler can be invoked to convert TypeScript to JavaScript.

3 .

When was the first time TypeScript was made public?

A)

October 2011

B)

October 2012

C)

October 2013

D)

October 2014

Correct Answer : October 2012

Explanation : TypeScript was first made public in October 2012 (at version 0.8), after two years of internal development at Microsoft.

4 .

TypeScript can always correctly infer a variables type.

A)

True

B)

False

C)

--

D)

--

Correct Answer : False

5 .

You can disable implicit variable type assignment by enabling the compiler option:

A)

noImplicitAny

B)

noAutoType

C)

Implicit = FALSE

D)

autoTypeAssignment = FALSE

Correct Answer : noImplicitAny

6 .

You can enable 'undefined' and 'null' types to be accounted for by enabling the compiler property:

A)

noAutoType

B)

noFalseyInits

C)

strictChecksRequired

D)

strictNullChecks

Correct Answer : strictNullChecks

7 .

Which of the following are features of typeScript?

A)

TypeScript is portable

B)

TypeScript is just JavaScript

C)

TypeScript supports other JS libraries

D)

All of the above

Correct Answer : All of the above

Explanation : All of the above are the Features of TypeScript.

8 .

Extension of typescript is?

A)

.d.tp

B)

.d.td

C)

.d.ts

D)

.d.ty

Correct Answer : .d.ts

Explanation : TypeScript Definition file (with .d.ts extension) provides definition for external JavaScript libraries.

9 .

TypeScript supports Object Oriented Programming concepts like classes, interfaces, inheritance.

A)

True

B)

False

C)

Can be true or false

D)

None of the above

Correct Answer : True

Explanation : TypeScript supports Object Oriented Programming concepts like classes, interfaces, inheritance.

10 .

A)

never

B)

similar

C)

unknown

D)

--

Correct Answer : unknown

11 .

What is the inherited type for the variable example in 'const example = ['Dylan']'?

A)

any[]

B)

string[]

C)

string

D)

unknown[]

Correct Answer : string[]

12 .

What does the 'readonly' access modifier do for an array variable assignment like: 'const codeNames: readonly string[] = ['Coding', 'God']'?

A)

Makes you read it for better clean code

B)

Allows only adding but not deleting elements in the array

C)

Makes it private and can only be used in the file its created

D)

Allows no changes and is there simply to be read from and not modified

Correct Answer : Allows no changes and is there simply to be read from and not modified

13 .

TypeScript will always correctly infer the type of an array.

A)

True

B)

False

C)

--

D)

--

Correct Answer : False

14 .

How many components typescript has?

A)

3

B)

4

C)

5

D)

6

Correct Answer : 3

Explanation : At its heart, TypeScript has the following three components : Language, The TypeScript Compiler and The TypeScript Language Service.

15 .

TypeScript is ?

A)

Case-sensitive

B)

Case-insensitive

C)

depends on typescript version

D)

None of the above

Correct Answer : Case-sensitive

Explanation : TypeScript is case-sensitive. This means that TypeScript differentiates between uppercase and lowercase characters.

16 .

TypeScript supports how many types of comments?

A)

1

B)

2

C)

3

D)

4

Correct Answer : 2

Explanation : TypeScript supports the following types of comments : Single-line comments And Multi-line comments.

17 .

True or False: a Tuple and an Array are the same thing when discussing types

A)

True

B)

False

C)

--

D)

--

Correct Answer : False

18 .

Which is a successful example of this tuple '[number, string]'?

A)

const ourTuple = [101]

B)

const ourTuple = ['Coding God', 101]

C)

const ourTuple = [101, 101, 'Coding God', 'Coding God']

D)

const ourTuple = [101, 'Coding God']

Correct Answer : const ourTuple = [101, 'Coding God']

19 .

Type Aliases are mostly used with ______.

A)

Strings

B)

Booleans

C)

Numbers

D)

None of the above

Correct Answer : Strings

20 .

Interfaces are similar to type aliases, but only for object types?

A)

True

B)

False

C)

--

D)

--

Correct Answer : True

21 .

________ an interface will have the same properties as that interface.

A)

Idolizing

B)

Improving

C)

Extending

D)

Duplicating

Correct Answer : Extending

22 .

What are the two types of enums?

A)

String and Boolean

B)

String and Number

C)

Number and Boolean

D)

Number and Number Array

Correct Answer : String and Number

23 .

Numeric enums first value is defaulted to what?

A)

0

B)

1

C)

5

D)

10

Correct Answer : 0

24 .

'keyof' can be used with index signatures to extract the index type.

A)

True

B)

False

C)

--

D)

--

Correct Answer : True

25 .

According to Grady Brooch, every object must have _________ features.

A)

1

B)

2

C)

3

D)

4

Correct Answer : 3

26 .

A ________ in terms of OOP is a blueprint for creating objects.

A)

method

B)

function

C)

constructor

D)

class

Correct Answer : class

Explanation : A class in terms of OOP is a blueprint for creating objects. A class encapsulates data for the object.

27 .

Definitely Typed is_____

A)

a superset of TypeScript

B)

the official name of TypeScript

C)

a project whose goal is to make types dynamic

D)

a project that provides a central repository of TypeScript definitions for NPM packages which do not have types

Correct Answer : a project that provides a central repository of TypeScript definitions for NPM packages which do not have types

28 .

What is the type of the parameter: 'function ex(param1?: string){}'?

A)

string

B)

string | undefined

C)

string | null

D)

unknown

Correct Answer : string | undefined

29 .

_____ is a return type for when nothing is returned.

A)

void

B)

any

C)

any[]

D)

unknown

Correct Answer : void

30 .

Access modifiers control the ______ of properties and methods.

A)

type

B)

mocking

C)

visibility

D)

inheritance

Correct Answer : visibility

31 .

protected modifiers only are allowed in the inherited class.

A)

True

B)

False

C)

--

D)

--

Correct Answer : False

32 .

public modifiers allow access to the class members from anywhere.

A)

True

B)

False

C)

--

D)

--

Correct Answer : True

33 .

Semicolons are optional in TypeScript.

A)

Yes

B)

No

C)

Can be yes or no

D)

None of the above

Correct Answer : Yes

34 .

When a class extends another class and replaces the members of its parent it is called what?

A)

Overload

B)

Inheriting

C)

Extending

D)

Override

Correct Answer : Override

35 .

Which are the different Data Types supported by Typescript?

A)

Boolean var bValue: boolean = false

B)

Number var age: number = 16

C)

String var name: string = "jon"

D)

All of the above

Correct Answer : All of the above

36 .

What are the three main 'simple types' in TypeScript?

A)

Object, Array, Symbol

B)

Array, Object, Boolean

C)

Boolean, Number, String

D)

Object, String, Number

Correct Answer : Boolean, Number, String

37 .

What type of assignment is this variable, 'const fullName: string = 'Dylan Israel';'?

A)

Implicit

B)

Explicit

C)

Both (A) and (B)

D)

None of the Above

Correct Answer : Explicit

38 .

Which statements are true regarding JSX modes?

A)

The react mode will emit React.addElement

B)

The output of react mode will have a .jsx file extension

C)

These modes only affect the emit stage - type checking is unaffected

D)

The preserve mode will keep the JSX as part of the output to be further consumed by another transform step

Correct Answer : The preserve mode will keep the JSX as part of the output to be further consumed by another transform step

39 .

What are variables in Typescript?

A)

A variable name should contain alphabets and numeric digits

B)

A variable name cannot begin with a digit

C)

It cannot contain spaces and special characters except underscore (_) and dollar ($) sign

D)

All of the above

Correct Answer : All of the above