What is Object-Oriented Programming in JavaScript?

What is Object-Oriented Programming in JavaScript?

Object-Oriented Programming (OOP) in JavaScript is a programming paradigm that uses objects to design applications. It allows for encapsulation, inheritance, and polymorphism.

Can you explain encapsulation with an example?

Sure! Encapsulation is the bundling of data and methods that operate on that data within one unit, usually a class. For example:

class Car {
  constructor(brand) {
    this.brand = brand;
  }
  getBrand() {
    return this.brand;
  }
}
const myCar = new Car('Toyota');
console.log(myCar.getBrand()); // Outputs: Toyota

What about inheritance? How does it work in JavaScript?

Inheritance allows one class to inherit properties and methods from another. In JavaScript, this can be done using the extends keyword. For example:

class Vehicle {
  constructor(type) {
    this.type = type;
  }
}
class Car extends Vehicle {
  constructor(brand) {
    super('Car');
    this.brand = brand;
  }
}
const myCar = new Car('Toyota');
console.log(myCar.type); // Outputs: Car

What is polymorphism in OOP?

Polymorphism allows methods to do different things based on the object it is acting upon. In JavaScript, this can be achieved through method overriding. For example:

class Animal {
  speak() {
    console.log('Animal speaks');
  }
}
class Dog extends Animal {
  speak() {
    console.log('Dog barks');
  }
}
const myDog = new Dog();
myDog.speak(); // Outputs: Dog barks