6.nested data access, evolution of function, constructor vs factory copy by value/ref

//accessing data from nested array and object
//copy by value vs copy be reference, pass by by value vs pass by reference
//constructor vs factory function
//Evolution of function
//nested loop

// const arr = [
//   'a',
//   'b',
//   'c',
//   'd',
//   ['e', 'f', ['g']],
//   function () {
//     return 'Hi'
//   },
//   'h',
//   'i',
// ]
// //accessing data by index
// console.log(arr[0])
// console.log(arr[4][1])
// console.log(arr[4][2][0])
// console.log(arr[4][2][0])
// console.log(arr[5]())

//array vs object

//accessing data from object
// const obj = {
//     a: "b",
//     c: {
//         d: "e",
//         f: {
//             g: "h"
//         }
//     },
//     i: function(){
//        return obj.a //b
//     }
// }

// console.log(obj.c.d)
// console.log(obj.c.f.g)
// console.log(obj.i())

//primitive data (string, number.....)
//complex data type or object (array, object, function)

//copy by value (primitive)
// let a = 10
// const b = a
// a = 20

// console.log(a, b)

// //copy by reference (object) (value is in in specific location)
// let aObj = {
//     value: {
//         a : 1
//     }
// }

// const bObj = JSON.parse(JSON.stringify(aObj))
// aObj.value.a = 2

// console.log(aObj, bObj)

//pass by value (primitive)

// function printByValue(a){
//     let b = a
//     a = 20
//     console.log(a)
//     console.log(b)

// }

// const a = 10
// printByValue(a)

//pass by reference (object type)
// function printByRef(aObj){
//     let bObj = aObj
//     aObj.value = 20
//     console.log(aObj)
//     console.log(bObj)

// }

// const aObj = {
//     value: 10
// }
// printByRef(aObj)
// console.log(aObj)

//Evolution of function
//function statement(? command)
// function sum(a, b){
//     return a + b
// }

//function expression(? value)
//10 , 20 , true, false

//expression can be written on right side of variable
// const sum = function(a, b){
//     return a + b
// }

//arrow function
// const sum = (a, b) => {
//     return a + b
// }

// const sum = (a, b) => a + b

// 2 ^ 4 = 2 *2 *2 *2
// const exponential = a => a ** 2

// console.log(exponential(10))

//constructor function vs factory function

// const user = {
//   firstName: 'samim',
//   lastName: 'Hasan',
//   age: 30,
//   fullName() {
//     return this.firstName + this.lastName
//   },
// }

//factory function
// function createUser(firstName, lastName, age) {
//   return {
//     firstName,
//     lastName,
//     age,
//     fullName() {
//       return this.firstName + ' ' + this.lastName
//     },
//   }
// }

// const samim = createUser('samim', 'Hasan', 30)
// const shanto = createUser('shanto', 'khan', 23)
// console.log(shanto)
// console.log(shanto.fullName())
// console.log(samim.fullName())

//constructor function
// function User(firstName, lastName, age) {
//    //{} == this
//    this.firstName = firstName
//    this.lastName = lastName
//    this.age = age
//    this.fullName = function(){
//     return this.firstName + ' ' + this.lastName
//    }
//    //return this
// }

// const samim = new User('samim', 'Hasan', 30)
//  const shanto = new User('shanto', 'khan', 23)
// console.log(samim.fullName())
// console.log(shanto.fullName())

//nested loop (primer)
// for(let i = 0; i < 3; i++){
//     console.log(i)
//     for(let j = 0; j < 3; j++){
//         console.log(i, j)
//     }
// }