JavaScript Classes

JavaScript Classes are templates for JavaScript Objects.


JavaScript Class Syntax

Use the keyword class to create a class.

Always add a method named constructor():

Syntax:

class ClassName {
  constructor() { ... }
}

Example:

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

The example above creates a class named "Car".

The class has two initial properties: "name" and "year".

A JavaScript class is not an object.

It is a template for JavaScript objects.


Using a Class

When you have a class, you can use the class to create objects:

The example below uses the Car class to create two Car objects.

The constructor method is called automatically when a new object is created.

EXAMPLE ❯


The Constructor Method

The constructor method is a special method:

It has to have the exact name "constructor"

It is executed automatically when a new object is created

It is used to initialize object properties

If you do not define a constructor method, JavaScript will add an empty constructor method.


Class Methods

Class methods are created with the same syntax as object methods.

Use the keyword class to create a class.

Always add a constructor() method.

Then add any number of methods.

Syntax:

class ClassName {
  constructor() { ... }
  method_1() { ... }
  method_2() { ... }
  method_3() { ... }
}

You can send parameters to Class methods:

EXAMPLE ❯