Day 11 Objects
Object ek data structure hai jo key-value pairs store karta hai. Real world entities represent karne ke liye — user, product, order — objects use karte hain.
Object Create karna
Curly braces {} se object banate hain.
// Object literal
let user = {
name: "Zohaib Arshad",
age: 25,
city: "Lahore",
isStudent: false,
skills: ["JavaScript", "React", "Next.js"]
};
// Access properties
console.log(user.name); // dot notation
console.log(user["city"]); // bracket notation
// Modify
user.age = 26;
user.email = "z@example.com"; // Add new property
// Delete
delete user.isStudent;
Methods — Functions inside Objects
Object ke andar functions bhi rakh sakte hain — inhe methods kehte hain.
let calculator = {
result: 0,
add(n) {
this.result += n;
return this; // chaining ke liye
},
subtract(n) {
this.result -= n;
return this;
},
getResult() {
return this.result;
}
};
// Method chaining
console.log(
calculator.add(10).add(5).subtract(3).getResult()
); // 12
Destructuring
Object se variables extract karna — clean aur modern way.
let user = {
name: "Ali",
age: 30,
city: "Karachi",
email: "ali@example.com"
};
// Old way
// let name = user.name;
// let age = user.age;
// Destructuring (modern)
let { name, age, city } = user;
console.log(name, age, city); // Ali 30 Karachi
// Rename while destructuring
let { name: userName, age: userAge } = user;
console.log(userName); // Ali
// Default values
let { country = "Pakistan" } = user;
console.log(country); // Pakistan
🎯 Practice Challenge
Product object banao: name, price, category, inStock, ratings. Ek method add karo jo discounted price return kare.