Classes And Objects

Class Definition

Class is a blueprint in which characteristics (properties) and behaviors (functions) are defined.

An example of class definition is:

class Person {}

In the example:

• class is the keyword for class defining.
• Person - the name of the class.

Object Creation

Object is an instance created from a class.

Using the defined class we can create objects and set properties.

class Person { introduceYourself() { console.log("I'm " + this.name + " and I'm " + this.age + " years old."); } } // create object let personObject = new Person(); // set properties personObject.name = "John"; personObject.age = 20; personObject.introduceYourself();

Output:

I'm John and I'm 20 years old.

Explanation:

• At lines 1 - 6 a class is defined.
• The class has a function introduceYourself that uses the properties of a class object via the this keyword.
• At line 9 an object is created.
• At lines 12 and 13 values are set to the members.
• At lines 15 the function introduceYourself is called and a message is printed.