Understanding Object in Javascript

What are objects and why they are needed?

In javascript an object is a collection of key-value pairs used to store information and data. Consider Aadhar Card, where you have your all data stored. Instead storing in seperate variables, we store this in one object.

let person = {
  name: "Rahul",
  age: 25,
  city: "Mumbai"
};

Here,

Key:name,age,city

values:"Rahul",25,"Mumbai"

Creating Objects:

//With curly
let person = {
  name: "Amit",
  age: 30,
  city: "Pune"
};

console.log(person);

//Output
{name: "Amit", age: 30, city: "Pune"}

//Each property is separated using a comma.

//Object Constructor
let person = new Object()

person.name = "Rahul"
person.age = 25
person.city = "Mumbai"

console.log(person)

//Function Construction
function Person(name, age, city) {
  this.name = name
  this.age = age
  this.city = city
}

let p1 = new Person("Rahul", 25, "Mumbai")
let p2 = new Person("Anita", 22, "Pune")

console.log(p1)
console.log(p2)

//Using Createlet personPrototype = {
  greet: function() {
    console.log("Hello!")
  }
}

let person = Object.create(personPrototype)

person.name = "Rahul"

person.greet()   // Hello!

Accessing Object Properties with Dot Notation and Bracket Notation

let person = {
  name: "Amit",
  age: 30,
  city: "Pune"
};

console.log(person);

//1.Dot Notation
console.log(person.name);
console.log(person.age);

//2.Bracket Notation
console.log(person["city"]);

Updating object Properties

let key = "name";

console.log(person[key]);
//Output:{name: "Amit", age: 31, city: "Pune"}

Adding New Properties

person.country = "India";

console.log(person);

//Output:{name: "Amit", age: 31, city: "Pune", country: "India"}

Deleting Properties

delete person.city;

console.log(person);

//Output:{name: "Amit", age: 31, country: "India"}

Looping Through Object Keys

for (let key in person) {
  console.log(key, person[key]);
}

//name Amit
//age 31
//country India

Hope you get the object glance.

Thank You!!!