JavaScript Object Methods

const person = {
  firstName: "John",
  lastName: "Doe",
  id: 5566,
  fullName: function() {
    return this.firstName + " " + this.lastName;
  }
};

In the example above, this refers to the person object :

this.firstName means the firstName property of person.

this.lastName means the lastName property of person.

Accessing Object Methods

You access an object method with the following syntax:

objectName.methodName()

If you invoke the fullName property with (), it will execute as a function:

name = person.fullName();

If you access the fullName property without (), it will return the function definition:

name = person.fullName;

Adding a Method to an Object

Adding a new method to an object is easy:

person.name = function () {
  return this.firstName + " " + this.lastName;
}

Using JavaScript Methods

This example uses the JavaScript toUpperCase() method to convert a text to uppercase:

person.name = function () {
  return (this.firstName + " " + this.lastName).toUpperCase();
};