Objects in Javascript:

What is object:

• An object is a collection of key-value pairs.
• The values of properties can be primitives, objects, or functions (known as methods when defined inside an object).

let person = {
    name: "ABC",
    age: 30,
    city: "Chennai"
};

console.log(person);

{name: "ABC", age: 30, city: "Chennai"}

1. Accessing Object Properties
1️⃣ Dot Notation

console.log(person.name);

2️⃣ Bracket Notation

console.log(person["age"]);

2. Modifying Object Properties

• It can be modified by reassigning its values.

let person= { name: "ABC", age: 30 };
console.log(person);

person.age=23//Modifying property
person.name="Test"

3. Adding Properties to an Object

You can dynamically add new properties to an object using dot or bracket notation.

person.country = "India";   // add

console.log(person);

4. Removing Properties from an Object
The delete operator removes properties from an object.

delete person.city;

console.log(person);

{name: "Anees", age: 31, country: "India"}

5. Checking if a Property Exists
You can check if an object has a property using the in operator

let person = { MobileNo: 1231231212 };
console.log("MobileNo" in person);

Adding objects with Methods
Objects can also store functions (called methods)

let person = {
    name: "And",
    greet: function() {
        console.log("Hello " + this.name);
    }
};

person.greet();

O/P:
Hello And

Looping through Object

let person = {
    name: "ABC",
    age: 30
};

for (let key in person) {
    console.log(key + ": " + person[key]);

O/P:
name: ABC
age: 30

Nested Objects
Objects inside objects

let user = {
    name: "ABC",
    address: {
        city: "Chennai",
        pincode: 600001
    }
};

console.log(user.address.city);

O/P:
Chennai

Array of Objects

let users = [
    { name: "ABC", age: 30 },//index 0
    { name: "John", age: 25 }//index 1
];
console.log(users[0].name);

O/P:
ABC