JavaScript Objects

In JavaScript, objects are complex data types that allow you to store and organize data in key-value pairs. Objects are used to represent real-world entities, and they are a fundamental part of the language.

In the below PDF we discuss about JavaScript Objects in detail in simple language, Hope this will help in better understanding.

Creating Objects:

There are two main ways to create objects in JavaScript:

1. Object Literal Syntax:


// Object literal syntax
let person = {
name: "John",
age: 30,
city: "New York"
};

2. Object Constructor Syntax:


// Object constructor syntax
let person = new Object();
person.name = "John";
person.age = 30;
person.city = "New York";

Object Examples:

let person = {
firstName: "John",
lastName: "Doe",
age: 30,
isStudent: false,
address: {
street: "123 Main St",
city: "Anytown",
zipCode: "12345"
},
sayHello: function() {
console.log("Hello, " + this.firstName + "!");
}
};

In this example:

firstName, lastName, age, and isStudent are properties of the person object.
address is an object property containing nested key-value pairs.
sayHello is a method (a function property) associated with the person object.

Accessing Object Properties:

You can access the properties of an object using dot notation or square bracket notation:

console.log(person.name); // Dot notation
console.log(person[“age”]); // Square bracket notation
Object Methods:
Objects can contain functions as values, and these are called methods. Methods are functions associated with an object:

let car = {
brand: "Toyota",
model: "Camry",
start: function() {
console.log("Engine started.");
},
stop: function() {
console.log("Engine stopped.");
}
};

car.start();
car.stop();

Nested Objects:

Objects can contain other objects as properties, creating nested structures:

let person = {
name: "John",
address: {
street: "123 Main St",
city: "Anytown",
zip: "12345"
}
};

console.log(person.address.city); // Accessing nested property