JavaScript Classes are templates for JavaScript Objects. 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:
Example
let myCar1 = new Car("Ford", 2014); let myCar2 = new Car("Audi", 2019);
The example above uses the Car class to create two Car objects.
The Constructor Method
The constructor method is called automatically when a new object is created. 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() { ... }
}
Create a Class method named “age”, that returns the Car age:
Example
class Car { constructor(name, year) { this.name = name; this.year = year; } age() { let date = new Date(); return date.getFullYear() - this.year; } } let myCar = new Car("Ford", 2014); document.getElementById("demo"). innerHTML = "My car is " + myCar.age() + " years old.";
You can send parameters to Class methods:
Example
class Car { constructor(name, year) { this.name = name; this.year = year; } age(x) { return x - this.year; } } let date = new Date(); let year = date.getFullYear(); let myCar = new Car("Ford", 2014); document.getElementById("demo"). innerHTML= "My car is " + myCar.age(year) + " years old."