Understanding and Practicing Object Type

JavaScript has 8 data types . 7 are primitive and 1 is complex object type. This is summary of T- class of cohort on 26 feb, 2026

// Objects 
//terminal 
mkdir t-5
code . // current directory me vscode snip up

1-object.js
8 data types 7 + 1
// properties : 
name-value pairs
// 2 ways of creeting objects
let claude = new Object() // object constructor syntax
let gemini = {}  // object literal

let gpt = {
company : 'openai',
version:5.3,
releaseYear:2025
}
// accessing properties
// gpt.company

// new properties
// property can be any type
gpt.type = 'Large Language Model' ;
gpt.isMultiModel = true // multiModel means can do many things

// remove properties 
delete gpt.type

// sonnet 
let sonnet = {
company :"anthrophic",
version : 4.6,
"released on": 2026, // trailing comma
}
// multi word property must be quotated

// square bracket notation
sonnet["released on"]
// valid identifier 
1. starting not from number
2. only $and _.

// property are string in objects
// expression as values as property name
const input = "company"
sonnet[input]

// property value shorthand
                            //params
function getLaptop(name, price) {
return {
brand : 'apple',
//property shorthand if key and value are same
name,
price 
}
}
let myMac = getLaptop("M4 Air", 99_000) // args
// myMac 

// check property exists or not
// ram propert or not
myMac.ram === undefined  // conditional always return boolean

// in method
"ram" in myMac // is there or not // key in object

// hasOwnProperty


// looping the objects 
// for in 

for(let key in myMac) {
console.log(`\({key} : \){myMac[key]}`)
}

// objects are ordered in different fashion
const codes = {
// Asia
7 : 'Russia',
32:'Belgium',
91:'India',

// North America
1:'Canada',
52:'Mexico'
}

// codes  { 1,4,32,52,91}

// integer properties got sorted in objects , other appear in creation order
for (let code in codes ) {
console.log(key)
}
// fixing it 
{
'+7': 'Russia',
'+32' : 'Belgium',
'+91':'India'
}

//Non Numeric properties
// Array, Date, Promise, Error


//Ref and copying
// primitives are always copied as "value"
let like = "Radhika Das" ;
le love = like ;

console.log(like, love)

// like : Taylor Swift
like = 'Taylor Swift' ;
console.log(love)

// Object are stored and copied by reference 
let artist  = {
name : "Radhika Das ",
country : "UK"
}

let Kirtaniya = artist ;
artist.country = "England" ;
// artist === Kirtaniya ;

// store by reference 
let a = {};
let b = {} ;
console.log(a === b )

// Const can't be modified  then how we modified objects

const ev = {
name : "Mahindra be6",
}
ev.name = "BYD Seal"  // new word : contracdictin

// ev

// we cannot do 
ev = {name : "Thar"}

// cloning and merging
const org = {
k1 : 'V1',
k2 : 'V2',
}
// why to clone becz cannot copy by value it taken ref 
const clone = {}
for (let key in org ) {
clone[key] = org[key] ;
}
// Object.assign(dest, soyrces .. )
let clone2 = Object.assign ({}, org) ;

// nested objects 
const nestedObj = {
model,
version ,
capabilities : {
reasoning}
}

// capabilities are ref 

// deep clone needed
structuredClone(nestedObj)
// nestedObj.capabilities.reasoning  = false
// it not change in nestedClone

// 02- Garbage Collection
// Reachability

let temp = {
emial : "gibbesis@xyz.com",
valid : 5
}
// yes it is reachable
// temp
// after 5 minutes it becomes invalid
temp = null
// temp // it is not point to the temp obj
// Garbage collector will junk the data and free the memory

const movie = {
title : 'Ghosted',
release : 2023,
production : 'Apple TV',
}
function coStars (actor, actress) {
actor.coStar = actress;
actress.coStar = actor
 return {
leading : actor,
supporter:actress
}
}
movie.cast = coStars({
name : 'Chris Evan' , salary : 10_000_000},
{name: 'Anna de Armas', salary: 2_000_000}
})
movie.cast = null
// garbage collector do clean it 

// 03- methods

function viralDance() {
//Ichu Ichu Song 
}

const dogesh  = {
name:'husky',
dance: viralDance
}

// activities by methods
dogesh.dance = function (){
// Ichu Ichu song
}


const dogesh  = {
name:'husky',
dance:function () {
//Ichu Ichu Song 
}
}

// shorthand method prop

const dogesh  = {
name:'husky',
dance() {
//Ichu Ichu Song 
}
}

// 
let user = {
name,
age,
college,
passedOut,
gf,
intro() {
// user.name
// user.age
// user.college
// user.gf
}
}

let piyush = user
user=null

piyush.intro()

// jessa sang use rang
// arrow is transparency glass
// this is just like chamelom
// contemplate

// 4 new operator 

// It is mostly used in constructor function
// used to construct object
// capital Name // first letter Capital
// should be executed by new operator

function User (name) {
this.name = name ;
this.isPaid = false ;
}

const anirudh = new User('Ani') ;  // User {}

// new does these things
this = {} ;
property assign
// return this


// optional chaining
const user = {
name, email,
address :{
full,
zip
}
}
// user.address.city
// agar address ho toh city me jana
// user.address ?.city
if(user.address){
if(user.address.city) {
// user.address.city
}
else {
// full address

}
else return ""
}

// logica or  returnn// first truthy and last truthy

// && first falsy and last truthy value

// Symbol 
// Object keys should be string and Symbol
// primitive unique value with description
let baby = Symbol("Ladla") ;

// Symbols are always unique even after its descriptions are same

// use case 
// hidden property , for in loop skip by 


// globalSymbol
// they exist in global symbol registry
let org = Symbol.for("Chaicode") ;

let company = Symbol.for("Chaicode") ;

Symbol.keyfor(org)

// System Symbol
Symbol.Iterator
Symbol.toPrimtive

// Date object add and subtract

[Symbol.toPrimitive](hint) {}

hint=> string,number,default
// default is concatenation
// toString

const galgota = {
status :"wasted",
aura:-1000,

[Symbol.toPrimitive](hint) {
if(hint === "string") return this.status
if(hint === "number") return this.aura
return this.aura
}
}

// number bigint string boolean null undefined Sybol
// null and undefined are pure primitive
// Boxing

// let str = ""
// Wrapper object create which gives access of methods

let million = 1_000_000 ;
million = 1e6 ;

// e is used to zero
let cr = 4e7 ;
// 4e1 40
// 4e9 
// 1e5
// 0xff // 0x hex
// 0b111 // binary
// 0o13  //


//Math.floor(Math.random() * (max-min+1)) + max-min ;

// min + Math.random() * (max-min)

// Json no trailing comma

Summary

This is all about basic object foundation in JavaScript. This is foundation and learn nee thing about the use of e for adding zero and also number system like hex, octal, binary etc.