Class

In JavaScript, classes were introduced with ECMAScript 6 (ES6) to provide a more convenient and structured way to create and work with objects.

Classes in JavaScript are syntactical sugar over the existing prototype-based inheritance and constructor functions.

They allow us to define a blueprint for creating objects with methods and properties.

Class Declaration:

To declare a class, we use the "class" keyword followed by the name of the class.

The class may contain a constructor method for initializing object instances, as well as other methods and properties.

Example:

class Person {
    constructor(name, age) {
        this.name = name;
        this.age = age;
    }

    greet() {
        console.log(`Hello, my name is ${this.name} and I am ${this.age} years old.`);
    }
}

Creating Instances:

We can create instances of a class using the new keyword.

Example:

const person1 = new Person("Alice", 33);
const person2 = new Person("Sarah", 22);

person1.greet(); // Outputs: Hello, my name is Alice and I am 33 years old.
person2.greet(); // Outputs: Hello, my name is Sarah and I am 22 years old.

Static Methods:

Example:

class MathOperations {
    static multiply(x, y) {
        return x * y;
    }

    static divide(x, y) {
        return x / y;
    }
}

console.log(MathOperations.multiply(10, 2));      // Outputs: 20
console.log(MathOperations.divide(8, 2)); // Outputs: 4

We can define static methods that are called on the class itself rather than on instances of the class.

Example:

 class Square {
    public _side;
    constructor(side) {
        this._side = side;
    }

    get side() {
        return this._side;
    }

    set side(newSide) {
        if (newSide > 0) {
            this._side = newSide;
        } else {
            console.error("Side must be greater than 0.");
        }
    }

    get area() {
        return this._side * this._side;
    }
}

const yourSquare = new Square(10);
console.log(yourSquare.side); // Outputs: 10
console.log(yourSquare.area);   // Outputs: 100

yourSquare.side = 4;
console.log(yourSquare.side); // Outputs: 4
console.log(yourSquare.area); // Outputs: 16

yourSquare.side = -2; // Error: Side must be greater than 0.

Getter and Setter Methods:

We can use getter and setter methods to control access to the properties of an object.

Note:

Classes provide a cleaner syntax for object-oriented programming in JavaScript and make it easier to work with object creation and inheritance.

They are widely used in modern JavaScript development.

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