Object in JavaScript

An object is a collection of properties (variables, other objects, & functions), and property is a combination of name (as key) and value. A property’s value can be a function, in this case, the particular property is called as a method. Above capabilities has made JS an OO paradigm.

Like other OO programming language, it can be explained by the real-life tangible objects in JavaScript.

Objects are variables:

JavaScript’s variables can contain single values, you can create your own variable and assign a value in it, which will work as an object.

var person = "John Doe";

However, objects can contain multiple variables. The variables are written as name: value pair.

var person = {
    firstName:"John",
    lastName:"Doe",
    age:50
};

A JavaScript object is a collection of name and value pairs.

Object name and value pair is similar to –

• Associative arrays in PHP
• Dictionaries in Python
• Hash tables in C

Object Methods:

An object method is properity which contains a function definition as a value.

var person = {
    firstName:"John",
    lastName:"Doe",
    age:50,fullName : function(){
            return this.firstName + this.lastName
   }
};

Accessing properties:

There are two ways to access the properties

1. Using dot notation

2. Using bracket notation

Using dot notation

You access the properties of an object with a simple dot-notation.

Syntex : objectName.propertyName

var person = {
    firstName:"John",
    lastName:"Doe",
    age:50,fullName : function(){
            return this.firstName + this.lastName
   }
};

person.firstName // John

To assign a value to a property

person.firstName = "Kery";

Using []notation

You access the properties of an object with a simple dot-notation.

Syntex : objectName['propertyName']

var person = {
    firstName:"John",
    lastName:"Doe",
    age:50,fullName : function(){
            return this.firstName + this.lastName
   }
};
person['firstName'] // John
person['firstName'] = "Kery";