Classes

In JavaScript, classes provide a way to define blueprints for creating objects. They allow you to encapsulate data and behavior into a single entity. Classes are a key concept in object-oriented programming (OOP) and are widely used in JavaScript for building web applications.

Creating a Class

To create a class in JavaScript, you can use the class keyword followed by the class name. Here's an example of a Rectangle class that represents a rectangle shape:

1class Rectangle {
2  constructor(width, height) {
3    this.width = width;
4    this.height = height;
5  }
6
7  calculateArea() {
8    return this.width * this.height;
9  }
10}

In this example, we define a Rectangle class with a constructor method that takes in width and height parameters. The constructor method is used to initialize the object's properties.

Creating Objects from a Class

Once a class is defined, you can create objects from it using the new keyword. Here's an example of creating a Rectangle object:

1const rectangle = new Rectangle(5, 7);
2console.log(rectangle); // Output: Rectangle { width: 5, height: 7 }

In this example, we create a rectangle object with a width of 5 and height of 7.

Accessing Methods

Objects created from a class can access the class methods using dot notation. Here's an example of calling the calculateArea method for the rectangle object:

1console.log(rectangle.calculateArea()); // Output: 35

In this example, we call the calculateArea method on the rectangle object and it returns the calculated area of the rectangle.

Classes in JavaScript provide a powerful way to organize and structure your code. They allow you to create objects with properties and methods, making your code more modular and reusable.

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class Rectangle {

  constructor(width, height) {

    this.width = width;

    this.height = height;

  }

​

  calculateArea() {

    return this.width * this.height;

  }

}

​

const rectangle = new Rectangle(5, 7);

console.log(rectangle.calculateArea()); // Output: 35