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🔹 What is an Object?

An object is a collection of data stored in key-value pairs.

👉 Real-life example:
A student has name, age, marks → all grouped together.

let student = {
  name: "Aditya",
  age: 20,
  marks: 85
};

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🔹 Object Properties

Properties are variables inside an object.

let student = {
  name: "Aditya",
  age: 20
};console.log(student.name); // Aditya
console.log(student["age"]); // 20

👉 Two ways to access:

• Dot notation → student.name
• Bracket notation → student["name"]

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🔹 Object Methods

Methods are functions inside an object.

let student = {
  name: "Aditya",
  greet: function() {
    return "Hello " + this.name;
  }
};console.log(student.greet()); // Hello Aditya

👉 this refers to the current object.

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🔹 Nested Objects

Objects inside another object.

let student = {
  name: "Aditya",
  address: {
    city: "Delhi",
    pincode: 110001
  }
};console.log(student.address.city); // Delhi

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🔹 Object.keys()

Returns all keys (property names) in an array.

let student = {
  name: "Aditya",
  age: 20
};console.log(Object.keys(student));
// ["name", "age"]

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🔹 Object.values()

Returns all values in an array.

console.log(Object.values(student));
// ["Aditya", 20]

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🔹 Object.entries()

Returns key-value pairs as arrays.

console.log(Object.entries(student));
// [["name", "Aditya"], ["age", 20]]

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🧠 Practice: Student Management System

🎯 Goal:

Store and manage student data using objects.

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✅ Example:

let student = {
  name: "Rahul",
  age: 21,
  marks: {
    math: 80,
    science: 75,
    english: 85
  },
  getTotal: function() {
    return this.marks.math + this.marks.science + this.marks.english;
  }
};// Access data
console.log(student.name);// Nested object
console.log(student.marks.math);// Method
console.log("Total Marks:", student.getTotal());// Keys, values, entries
console.log(Object.keys(student));
console.log(Object.values(student));
console.log(Object.entries(student));

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🚀 Mini Project (Multiple Students)

let students = [
  {
    name: "Amit",
    age: 20,
    marks: 80
  },
  {
    name: "Priya",
    age: 22,
    marks: 90
  }
];// Loop through students
students.forEach(function(stu) {
  console.log(stu.name + " - " + stu.marks);
});

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🔥 Practice Tasks for Students

1. Create an object for 5 students
2. Add a method to calculate average marks
3. Print all student names using Object.keys()
4. Find student with highest marks
5. Add nested object for address