objects.md

// Javascripts objects are always in key value pair

let obj = {}; //empty object
console.log(obj);

Output

{}

//person object
let person = {
  //key(property,method()) : value
  name: "Abhishek",
  age: 28,
  phone: 9999999999,
  gender: "Male",
  height: "170cm",
};

console.log(`Hey ${person.name}, thank you for signing up !`);
console.log(person.gender);
console.log(person["gender"]);

Output

Hey Abhishek, thank you for signing up !
Male
Male

let str = "Hello";
console.log(str.length); //dot notation
console.log(str["length"]); //square bracket notation

Output

5
5

Nesting of objects

let captainAmerica = {
  firstName: "Steve",
  lastName: "Rogers",
  friends: ["Bucky", "Tony Stark", "Brue Banner"],
  age: 102,
  isAvenger: true,
  address: {
    state: "Manhattan",
    city: "New York",
    country: "USA",
  },
  sayHi: function () {
    console.log(`Hello my name is ${this.firstName}`);
  },
};

console.log(captainAmerica);
console.log(captainAmerica.friends);
console.log(captainAmerica.friends[0]);
captainAmerica.sayHi(); //method accessing

Output

//for loop
// in keyword in JS is used to get keys from that object
for (let haathi in captainAmerica) {
  //key
  console.log(haathi);
  // hathi jo varibale h uske andar meri key ki value padi hui h
  //value
  // varibale ke andar jo binded value h wo chahiye
  console.log(captainAmerica[haathi]); //bracket notation usage
}

// str{
//     length: //
//     toUpperCase: function() {

//         for()
//     }
// }

// methods-> objects ke andar function
// console.log(str.toUpperCase());

let arr = ["a", "b", 1, true];

let arrr = {
  0: "a",
  1: "b",
  2: 1,
  3: true,
};