BudiBaduQuiziBadu

TypeScript Functions and Parameters Quiz

TypeScript
0 Passed
0% acceptance

A 30-question TypeScript quiz covering function declarations, expressions, parameter types, optional and default parameters, rest arguments, and return type handling.

30 Questions
~60 minutes
1

Question 1

Which syntax defines a function declaration?

A
function add(a, b) { return a + b }
B
const add = (a, b) => a + b
C
add: function(a, b)
D
method add(a, b)
2

Question 2

Which statement is true about function expressions?

A
They assign a function value to a variable
B
They always require names
C
They cannot accept parameters
D
They must be exported
3

Question 3

What is the type of fn?

typescript
const fn = (x: number): number => x * 2;
A
(x: number) => number
B
number
C
any
D
(x: string) => string
4

Question 4

Why is it helpful to annotate a function's return type?

A
It prevents unintended changes to return values
B
It speeds up runtime execution
C
It hides type errors
D
It forces all parameters to be optional
5

Question 5

Which is a valid function type annotation?

A
let add: (a: number, b: number) => number
B
let add: function(a: number)
C
let add => number
D
let add(): number
6

Question 6

What does this parameter list mean?

typescript
function greet(name: string, age?: number) {}
A
age is optional
B
age must be provided always
C
name is optional
D
Both are optional
7

Question 7

Which is true about optional parameters?

A
They automatically become type | undefined
B
They cannot have explicit types
C
They must always be the first argument
D
They disable type checking
8

Question 8

What type does TypeScript infer for the return value?

typescript
function add(a: number, b: number) { return a + b; }
A
number
B
any
C
unknown
D
void
9

Question 9

Which statement about parameter types is correct?

A
Every parameter can be typed individually
B
All parameters must share one type
C
TypeScript forbids mixing typed and untyped parameters
D
Types are only allowed on return values
10

Question 10

What does the parameter type indicate?

typescript
function log(value: string | number) {}
A
value may be a string or a number
B
value must be a string only
C
value is optional
D
value is a function
11

Question 11

What is true about default parameters?

A
They apply when a value is undefined
B
They override provided arguments
C
They must be the first parameter
D
They cannot have explicit types
12

Question 12

What value does this function return?

typescript
function multiply(a: number, b: number = 2) {
  return a * b;
}
multiply(5);
A
10
B
5
C
undefined
D
Error
13

Question 13

Which syntax defines a rest parameter?

A
...args: number[]
B
args...
C
rest args[]
D
args: rest
14

Question 14

What does total receive?

typescript
function sum(...nums: number[]) {
  return nums.length;
}
sum(1, 2, 3);
A
An array containing [1,2,3]
B
Only the last argument
C
The first argument only
D
undefined
15

Question 15

Which rule applies to rest parameters?

A
They must be the final parameter
B
They cannot have types
C
They cannot be used with arrays
D
They only accept strings
16

Question 16

What is the inferred return type?

typescript
function hello() {
  return 'hi';
}
A
string
B
any
C
void
D
unknown
17

Question 17

When is it useful to annotate return types?

A
When inferring might hide subtle bugs
B
Only in async functions
C
Only when parameters are optional
D
Whenever using var
18

Question 18

Which return type indicates a function never finishes?

A
never
B
void
C
undefined
D
null
19

Question 19

What is the return type?

typescript
function fail(msg: string): never {
  throw new Error(msg);
}
A
never
B
void
C
string
D
unknown
20

Question 20

What does void represent as a return type?

A
A function that returns nothing
B
A function that returns undefined explicitly
C
A function that returns any value
D
A function that must throw
21

Question 21

What is the type of this function?

typescript
const fn = function(a: number, b: number): number {
  return a + b;
};
A
(a: number, b: number) => number
B
number
C
any
D
void
22

Question 22

What does a function overload define?

A
Multiple call signatures for the same function
B
Multiple return values at once
C
Alternate variable declarations
D
A new scope block
23

Question 23

Which statement about arrow functions is correct?

A
Their return type can be inferred or annotated
B
They cannot have typed parameters
C
They must always return void
D
They create new scopes for this binding
24

Question 24

What rule applies to optional parameters?

A
They must come after required parameters
B
They must be the first parameter
C
They require a default value
D
They cannot have types
25

Question 25

Which pattern ensures a function always returns a string?

A
Annotating the return type as : string
B
Omitting return entirely
C
Using var inside the function
D
Declaring no parameters
26

Question 26

Which keyword is used for asynchronous functions?

A
async
B
await
C
asyncfn
D
promise
27

Question 27

What is the return type of an async function?

A
Promise<ReturnValue>
B
ReturnValue only
C
never
D
void always
28

Question 28

Rest parameters are useful because they:

A
Allow a function to accept unlimited arguments
B
Guarantee faster execution
C
Remove the need for optional parameters
D
Disable type checking
29

Question 29

Which type best represents a function with no parameters and no return value?

A
() => void
B
() => never
C
(arg: any) => any
D
() => undefined
30

Question 30

Why is typing parameters important?

A
It ensures functions receive the right kinds of data
B
It changes runtime behaviour
C
It prevents using arrow functions
D
It disables inference

Other Quiz Categories

JavaScript
47 quizzes
Basics
Variables & Data Types
Operators & Expressions
Rust
30 quizzes
Cargo and Project Setup
Variables and Mutability
Data Types
Python
29 quizzes
Introduction & Core Fundamentals
Data Types Overview
Type Casting
Golang
29 quizzes
Basics & Syntax
Data Types & Zero Values
Operators & Expressions
C++
26 quizzes
Basics
Variables & Data Types
Operators & Expression
Java
22 quizzes
Java Basics & JVM Fundamentals
Variables, Data Types & Type Casting
Operators & Expressions
Matlab
21 quizzes
Basics & Environment
Variables and Data Type
Arrays and Matric
SQL Database
15 quizzes
Foundations and Basics
Basic Query Selection
Filter, Sort, and Alias Essentials
PHP
15 quizzes
Syntax Building Blocks
Variable Naming
Data Types Overview
Linked List
11 quizzes
Introduction
Node Structure and Pointer Fundamentals
Singly Linked List

QUIZZES IN TypeScript

1

Introduction and Overview

40

Test your foundational knowledge with 40 questions on TypeScript—covering its purpose, differences from JavaScript, benefits, compilation, and real-world applications.

2

Installation and Configuration

30

A 30-question TypeScript quiz covering installation, project setup, tsconfig.json fundamentals, compiler options, integrating build tools, project organization patterns, and how to run and compile TypeScript effectively.

3

Basic Types and Type Annotations

40

A 40-question TypeScript quiz covering primitive types, type inference, explicit annotations, arrays, tuples, object types, unions, intersections, and literal types.

4

Variables and Constants

35

A 35-question TypeScript & JavaScript quiz covering variable declarations, scope rules, hoisting, reassignment behavior, constants, immutability concepts, shadowing, and best practices for naming variables.

5

Functions and Parameters

30

A 30-question TypeScript quiz covering function declarations, expressions, parameter types, optional and default parameters, rest arguments, and return type handling.

6

Interfaces and Type Aliases

40

A 40-question TypeScript quiz covering interfaces, type aliases, structural typing, merging behavior, call signatures, index signatures, intersections, unions, and interface augmentation.

7

Classes and Objects

40

A 40-question TypeScript quiz focusing on classes, constructors, access modifiers, readonly fields, methods, inheritance, abstract classes, and object-based typing.

8

Enums and Tuples

40

A 40-question TypeScript quiz covering numeric enums, string enums, const enums, reverse mapping, tuple types, readonly tuples, labeled tuples, and practical usage patterns.

9

Union and Intersection Types

40

A 40-question TypeScript quiz covering union types, narrowing, discriminated unions, intersections, type composition, compatibility, and real-world modelling.

10

Literal Types and Type Inference

35

A 35-question TypeScript quiz about literal types, inference behavior, widening rules, const contexts, and practical modelling using specific literal values.

11

Generics

40

A 40-question TypeScript quiz exploring generic type parameters, constraints, generic functions, interfaces, classes, defaults, inference, and advanced patterns.

12

Type Assertions and Type Guards

40

A 40-question TypeScript quiz exploring type assertions, narrowing with guards, typeof checks, instanceof checks, custom predicate guards, discriminated unions, and safe narrowing patterns.

13

Optional and Default Parameters

30

A 30-question TypeScript quiz exploring optional parameters, default parameter values, undefined handling, rest parameters, function declaration rules, and parameter type inference.

14

Readonly and Immutability

30

A 30-question TypeScript quiz covering readonly properties, immutable arrays and tuples, const behavior, structural immutability, shallow freezing, and readonly utility types.

15

Modules and Namespaces

30

A 30-question TypeScript quiz covering ES module imports, exports, module resolution rules, namespaces, namespace merging, ambient modules, and organizational patterns.

16

Decorators

35

A 35-question TypeScript quiz covering decorator fundamentals, class decorators, method and property decorators, decorator factories, metadata reflection, and execution order.

17

Function Overloads

35

A 35-question TypeScript quiz covering overload signatures, implementation signatures, narrowing behavior, return types, and best practices for overloaded functions.

18

Abstract Classes and Access Modifiers

40

A 40-question TypeScript quiz covering abstract classes, abstract methods, public/private/protected access, readonly properties, inheritance behavior, and visibility constraints.

19

Mixins and Composition

40

A 40-question TypeScript quiz covering mixin patterns, composition techniques, mixin constraints, function-based class factories, multiple mixin stacking, and practical patterns.