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JavaScript Objects: How to Create and Delete Objects in JavaScript

Reading time 3 min
Published Aug 8, 2017
Updated Oct 15, 2019

JavaScript is heavily reliant on objects. The most used type of data in JavaScript is considered to be the object. JavaScript objects have properties and methods.

In this tutorial, you'll learn all about objects JavaScript holds, creating and handling them. Correct syntax of writing a JavaScript object will also be covered. You will understand JavaScript object properties and methods, defining and using them.

JavaScript Objects: Main Tips

  • JavaScript, just like many other computer languages, is based on objects.
  • To better understand the concept, JavaScript objects can be compared to real life objects.
  • JavaScript object is an independent entity. It has its methods and properties.
  • A property's value may be a function, in which case the property is known as a method.
  • Do not declare numbers, strings, and booleans as objects.
  • JavaScript object properties can be accessed in two ways: human.firstName and human["firstName"].

Real Life Example

In real life, a bike is an object. A bike has properties like color and height, and methods like drive and break:

Object Properties Methods
JavaScript Objects bike.name = mountain300;
bike.weight = 15kg;
bike.color = black;
bike.drive()
bike.break()

All bikes have the same properties, but their values are different for each bike. Also, all bikes have the same methods, but they can be executed at different times.

Theory is great, but we recommend digging deeper!

Objects in Variables

Variables in JavaScript are used for storing data. A JavaScript object is data signed to a variable. In the editor example below, you can see that the value mountain300 is assigned to a variable bike. The value mountain300 instantly becomes a JavaScript object:

Example
var bike = "mountain300";

JavaScript objects are also variables, but they can have more than one value assigned. The example below assigns multiple values to the bike variable: mountain300, 15, black.

To write multiple values, you need to use the right syntax. The values are assigned to names, and name: value combinations are formed:

Example
var bike = {
  title: "mountain300", 
  weight: "15", 
  color: "black"
};

Note: the values a JavaScript object contains are called properties.

Methods You Might Use

Methods represent actions which can be performed on JavaScript objects. Just like you've seen in the example with a bike before, a bike can be driven and stopped using brakes. In this case, drive and brake are the methods that can be used on the bike object.

Methods are stored in properties as function definitions:

Property Property Value
title mountain300
weight 15
price 210
color black
info function() {return this.title + " " + this.price;}

You already know how to access JavaScript objects' properties, so you may have a general idea of how the object methods can be accessed. The JavaScript object syntax is a bit different but relatively simple.

Example
name = human.fullName();

In case you access the fullName property without the parentheses (), the function definition will be returned instead of the value:

Example
name = human.fullName;

JavaScript Objects: Summary

  • JavaScript objects have properties and methods.
  • JavaScript object properties are assigned as name: value pairs.
  • javaScript object method is a property that is a function.