JavaScript Objects

JavaScript objects are used to store related information together using key-value pairs.

What is a JavaScript Object?

A JavaScript object is a collection of related data stored using key-value pairs.

Each key describes a piece of information and the value stores the actual data associated with that key.

Why Do We Use Objects?

Objects help us keep related information together instead of storing every value in a separate variable.

For example, a student can have a name, age, course, and city inside one object.

JavaScript Object - Key-Value Structure and Object Properties

Object Structure

An object is written using curly braces { }. Inside the braces, properties are written as key-value pairs.

let student = {
    name: "Amit",
    age: 22,
    course: "JavaScript"
};

How JavaScript Objects Store Data

Object Key-Value Structure

student

name : "Amit"

age : 22

course : "JavaScript"

→

Key → Value

name → Amit

age → 22

course → JavaScript

Each property contains a key and its corresponding value inside the JavaScript object.

Common Object Properties

name

Name Property

Stores the name or title related to the object.

age

Age Property

Stores a numeric value such as a person's age.

course

Course Property

Stores information about a course or subject.

city

City Property

Stores location-related information.

Example 1: Creating an Object

We can create an object using curly braces and define its properties using key-value pairs.

let student = {
    name: "Amit",
    age: 22,
    course: "JavaScript"
};

console.log(student);

Output: { name: "Amit", age: 22, course: "JavaScript" }

Example 2: Accessing Object Properties

We can access an object's property using dot notation.

let student = {
    name: "Amit",
    course: "JavaScript"
};

console.log(student.name);
console.log(student.course);

Output:
Amit
JavaScript

Example 3: Updating an Object Property

Existing property values can be changed by assigning a new value to the property.

let student = {
    name: "Amit",
    age: 22
};

student.age = 23;

console.log(student.age);

Output: 23

Example 4: Adding a New Property

A new property can be added to an existing object by assigning a value to a new property name.

let student = {
    name: "Amit",
    course: "JavaScript"
};

student.city = "Pune";

console.log(student.city);

Output: Pune

Summary

JavaScript objects are used to store related information using key-value pairs. Objects can contain multiple properties, and we can create, access, update, and add properties as required.