How to Define Classes in JavaScript

JavaScript introduced the

   class

syntax in ES6, providing a cleaner and more intuitive way to write object-oriented code. While classes in JS are syntactic sugar over prototypes, they offer structure and readability for developers.

1. Creating a Basic Class

Here’s how to define a simplePersonclass:

    class Person {
    constructor(firstName = "Unknown", lastName = "Unknown") {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    getFullName() {
        return `${this.firstName} ${this.lastName}`;
    }
    }

    const person1 = new Person("Alice", "Brown");
    console.log(person1.getFullName()); // Output: Alice Brown

2. Adding Methods to a Class

Methods define actions that class instances can perform:

    class Car {
    constructor(model, year) {
        this.model = model;
        this.year = year;
    }

    getInfo() {
        return `Model: ${this.model}, Year: ${this.year}`;
    }
    }

    const car1 = new Car("Toyota", 2020);
    console.log(car1.getInfo()); // Output: Model: Toyota, Year: 2020

3. Using Getters and Setters

Getters and setters let you control access to properties. Useful for validation or computed properties.

    class Product {
    constructor(name, price) {
        this._name = name;
        this._price = price;
    }

    get name() {
        return this._name;
    }

    set name(newName) {
        if (newName.trim()) {
        this._name = newName;
        } else {
        console.error("Name cannot be empty.");
        }
    }
    }

    const product1 = new Product("Laptop", 1500);
    console.log(product1.name); // Output: Laptop
    product1.name = ""; // Error: Name cannot be empty.

4. Inheritance (Extending a Class)

Use theextendskeyword to create a subclass:

    class Animal {
    constructor(name) {
        this.name = name;
    }

    speak() {
        return `${this.name} makes a noise.`;
    }
    }

    class Dog extends Animal {
    speak() {
        return `${this.name} barks.`;
    }
    }

    const dog = new Dog("Buddy");
    console.log(dog.speak()); // Output: Buddy barks.

5. Summary

class introduces clearer OOP syntax in JavaScript (ES6).
constructor() sets initial properties for new objects.
Methods define reusable actions for class instances.
Getters/Setters provide encapsulated access to properties.
Inheritance allows extending functionality from another class.