Javascript Object Methods

In this tutorial, you’ll learn about JavaScript object methods and how to define methods for an object.

Introduction to the JavaScript object methods

An object is a collection of key/value pairs or properties. When the value is a function, the property becomes a method. Typically, you use methods to describe the object’s behaviors.

For example, the following adds the greet method to the person object:

let person={
  firstname:"Anup",
  lastname:"Maurya"
}

person.greet = function () {
    console.log('Welcome to India!');
}

person.greet();

Output:

Welcome to India!

In this example:

• First, use a function expression to define a function and assign it to the greet property of the person object.
• Then, call the method greet() method.

Besides using a function expression, you can define a function and assign it to an object like this:

In this example:

• First, define the greet() function as a regular function.
• Second, assign the function name to the greet property of the person object.
• Third, call the greet() method.

Object method shorthand

JavaScript allows you to define methods of an object using the object literal syntax as shown in the following example:

let person = {
    
  firstname:"Anup",
  lastname:"Maurya",
    greet: function () {
         console.log('Welcome to India!');
    }
};

ES6 provides you with the concise method syntax that allows you to define a method for an object:

const person ={
   firstname:"Anup",
   lastname:"Maurya",
   greet(){
       console.log("Welcome to India!")
   }
}

This syntax looks much cleaner and less concise.

What is this in JavaScript?

In JavaScript, the this keyword refers to an object.

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

Which object depends on how this is being invoked (used or called).

The this keyword refers to different objects depending on how it is used: