Master Object-Oriented JavaScript: Classes, Objects, and Inheritance

Question 1

Which characteristic of object-oriented programming does NOT apply to JavaScript?

Accepted Answer

Modularity

Answer

Encapsulation

Answer

Abstraction

Answer

Inheritance

Question 2

In object-oriented JavaScript, what is the function of a class?

Accepted Answer

Provides a blueprint for creating objects

Answer

Stores data permanently

Answer

Performs mathematical computations

Answer

Controls the flow of program execution

Question 3

In JavaScript, which syntax correctly creates an object using a class?

Accepted Answer

var object = new ClassName();

Answer

var object = ClassName();

Answer

var object = ClassName;

Answer

var object = create();

Question 4

Describe the primary distinction between inheritance and polymorphism in object-oriented programming.

Accepted Answer

Inheritance establishes a static relationship, whereas polymorphism exhibits dynamic behavior.

Answer

Polymorphism establishes a static relationship, whereas inheritance exhibits dynamic behavior.

Answer

Both inheritance and polymorphism are inherently static concepts.

Answer

Both inheritance and polymorphism are inherently dynamic concepts.

Question 5

Which of the following is a significant advantage of adopting object-oriented programming in JavaScript?

Accepted Answer

Enhanced code reusability

Answer

Simplified debugging processes

Answer

Increased application performance

Answer

Improved security measures

Question 6

Explain the difference between a method and a constructor in OOP.

Accepted Answer

Methods operate on objects, while constructors are used to initialize and create objects.

Answer

Constructors operate on objects, while methods are used to initialize and create objects.

Answer

Both methods and constructors are used to create objects.

Answer

Both methods and constructors operate on objects.

Question 7

Identify the option that is NOT a built-in object in JavaScript.

Accepted Answer

User

Answer

Array

Answer

String

Answer

Document

Question 8

What is the primary purpose of arrow function syntax in JavaScript?

Accepted Answer

Provides a concise way to write function expressions

Answer

Improves the performance of code

Answer

Enhances the readability of code

Answer

Replaces the need for traditional function declarations

Question 9

In object-oriented programming, which principle enables objects to inherit the characteristics and behaviors of their parent class?

Accepted Answer

Inheritance

Answer

Encapsulation

Answer

Polymorphism

Question 10

Which of the following is NOT a characteristic of an object in JavaScript?

Accepted Answer

Is once created and cannot be changed

Answer

Consists of properties and methods

Answer

Is an instance of a class

Answer

Can be dynamically modified

Question 11

What is the primary purpose of the `this` keyword in JavaScript?

Accepted Answer

References the current object

Answer

Creates a new object

Answer

Inherits properties from a parent class

Answer

Defines a class method

Question 12

Which method in JavaScript is used to create a new instance of a class?

Accepted Answer

new

Answer

createObject()

Answer

createInstance()

Answer

instantiate()

Question 13

What is the purpose of the constructor method in JavaScript?

Accepted Answer

Initializes properties and methods for a newly created object

Answer

Defines the properties and methods of a class

Answer

Inherits properties and methods from a parent class

Answer

Calls other methods to perform specific tasks

Question 14

Which of the following is an example of method overriding in object-oriented programming?

Accepted Answer

Defining a method with the same name in a child class that provides a different implementation than the parent class

Answer

Redefining a property with the same name in a child class

Answer

Calling a method from a parent class within a child class method

Answer

Using the `super` keyword to access a property from a parent class

Question 15

What is the main objective of encapsulation in object-oriented programming?

Accepted Answer

To conceal the implementation details of an object from other parts of the program

Answer

To facilitate unrestricted communication between objects

Answer

To enhance the performance of the program

Answer

To improve the readability and maintainability of the code

Question 16

Is JavaScript exclusively an object-oriented programming language?

Accepted Answer

No

Answer

Yes

Question 17

In React, how does the use of class components embody object-oriented programming principles?

Accepted Answer

React leverages classes to define templates for reusable components.

Answer

React class components serve as a means to declare global variables.

Answer

Classes in React are unrelated to object-oriented programming concepts.

Question 18

Which keyword is used to define a class in JavaScript?

Accepted Answer

class

Answer

function

Answer

object

Answer

constructor

Question 19

What is the key distinction between methods and properties in JavaScript?

Accepted Answer

Methods are functions that operate on an object, while properties are data associated with an object.

Answer

There is no difference between methods and properties.

Answer

Methods are objects, while properties are functions.

Answer

Properties are functions, while methods are objects.

Question 20

Which of the following is the correct syntax for class extension in JavaScript?

Accepted Answer

extends

Answer

super

Answer

inherits

Answer

prototype

Question 21

What is the primary role of the 'this' keyword in JavaScript?

Accepted Answer

To reference the current object within a method or constructor

Answer

To create new objects

Answer

To access global variables

Answer

To define the class

Question 22

What is the main purpose of the 'super' keyword in JavaScript?

Accepted Answer

To call the constructor and methods of the parent class within a child class

Answer

To access global variables

Answer

To create new objects

Answer

To define the child class

Question 23

Which of the following is a recommended best practice in object-oriented JavaScript design?

Accepted Answer

Using descriptive and meaningful variable names

Answer

Declaring as many global variables as possible

Answer

Avoiding the use of classes

Answer

Duplicating code to avoid inheritance