Lecture 205:- Class

In JavaScript, a class is a blueprint for creating objects that have the same properties and methods. It defines a set of properties and methods that will be shared by all instances of the class. Classes are used to create objects that have a similar structure and behavior, making it easier to manage code and create reusable code.

In JavaScript, classes were introduced in ECMAScript 6 (ES6) as a new syntax for creating objects. Before ES6, JavaScript used a prototype-based inheritance model to create objects.

To define a class in JavaScript, you use the class keyword followed by the name of the class. You can then define a constructor method, which is called when an object is created from the class, as well as any other methods and properties that the class should have.

Here is an example of a simple class definition in JavaScript:

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class Person {  constructor(name, age) {    this.name = name;    this.age = age;  }    sayHello() {    console.log(`Hello, my name is ${this.name} and I am ${this.age} years old.`);  } } let person1 = new Person("John", 30); let person2 = new Person("Jane", 25); person1.sayHello(); // Output: Hello, my name is John and I am 30 years old. person2.sayHello(); // Output: Hello, my name is Jane and I am 25 years old.

In this example, we define a Person class with a constructor that takes two parameters, name and age, and sets them as properties of the class. We also define a sayHello method that logs a message to the console.

We then create two instances of the Person class, person1 and person2, and call the sayHello method on each of them to output a message to the console.