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Day 27Data Structures2 Hours Practical

Push to GitHub to Complete

JavaScript Objects, Nested Data & JSON Serialization Basics

Objects are keyed collections of properties and values. Everything in web applications—from user accounts to API responses from servers—is modeled using objects and JSON (JavaScript Object Notation).

Interactive Learning Roadmap

Day 27 Step-by-Step Practical Flow

🎯1. What You Will Learn Today

✔Model complex real-world entities using JavaScript object literals { key: value }.

✔Access and modify properties using dot notation and bracket notation.

✔Work with nested objects and arrays of objects (APIs dataset format).

✔Serialize objects to string using JSON.stringify() and deserialize with JSON.parse().

Day 27 MasterclassData Structures

JavaScript Objects, Nested Data & JSON Serialization Basics — Comprehensive Practical Guide

Har concept ko visual mental models, code anatomy aur practical industry tips ke sath samjhein.

Real-World Purpose Aur Zaroorat

Object literal: const obj = { key: "value", age: 20 };

Dot notation: obj.key — convenient when property name is a known valid identifier.

Bracket notation: obj["key"] — required when property name is dynamic or contains special characters/spaces.

JSON.stringify(obj): Converts a JavaScript object into a JSON string suitable for network transfer or localStorage.

JSON.parse(jsonString): Parses a JSON string back into a live JavaScript object.

Object Destructuring: const { name, roll } = student extracts properties directly into standalone variables.

Dimaag Mein Bithane Ka Model

"Think of an object like a student physical locker with labeled compartments: one label says "Roll Number", another says "Course", another holds a notebook with "Grades". JSON is like flattening all locker contents into a clean text inventory sheet to mail to university headquarters."

💡 Pro Tip: Code ko ratta mat maaro; imagine karo ki browser har tag ko visually kaise draw karta hai.

👨‍🏫3. Teacher Demonstration Code

See how properties, nested objects, and JSON serialization work together in application data management.

Creating Student Profile Object and Serializing to JSONhtml

<!DOCTYPE html>
<html>
<body>
  <script>
    const student = {
      id: "BCA-2026-001",
      name: "Diya Patel",
      semester: 1,
      subjects: ["Computer Basics", "C Programming", "Discrete Mathematics"],
      address: {
        city: "New Delhi",
        pincode: 110001
      }
    };

    console.log("Student Name:", student.name);
    console.log("City:", student.address.city);

    // Convert object to JSON string (Serialization)
    const jsonString = JSON.stringify(student);
    console.log("JSON String:", jsonString);

    // Parse back to object (Deserialization)
    const reconstructed = JSON.parse(jsonString);
    console.log("Reconstructed Name:", reconstructed.name);
  </script>
</body>
</html>

2. Hands-On Practical Lab: Follow Instructions in VS Code

Code like a professional software engineer! Follow the step-by-step instructions below in Visual Studio Code (VS Code) on your PC, test your output locally, and push to GitHub.

2 Coding Tasks

Interactive Coding TestAuto-Evaluates as you type

Day 27 Practical Task Test Studio

Test Score:0 / 2 Passed

1. Practical Task Specifications & Live Test Checklist:Type code below to pass tests

Task 1Create studentRecord object

Define const studentRecord = { rollNo: 101, name: "Kavya", isEnrolled: true };

⏳ WAITING

Task 2Serialize to JSON string

Declare const studentJson = JSON.stringify(studentRecord); and log it to console.

⏳ WAITING

2. Type HTML & CSS Code:index.html

index.html

⚡ Real-Time Testing Active

Tab inserts 2 spaces • Live DOM refresh219 chars

Live Browser Output:

🔒 http://localhost:5500/index.html

Live

Renders live HTML & CSS typed on the left.

Interactive Bug Detective

Spot the Bug: Accessing Undefined Nested Property Crash

Tap or click on the exact line below that contains the error:

Click any code line

⚠️ Broken Code Inspector

Tap buggy line

const student = {

name: "Vikram"

// address property is not defined

};

console.log(student.address.city); // Throws TypeError: Cannot read properties of undefined!

Stuck? Need a detective clue before checking the solution?

Senior Developer Forensic Analysis:

student.address evaluates to undefined. Attempting to access .city on undefined immediately throws an unhandled TypeError: Cannot read properties of undefined.

Golden Rule: Always validate code syntax and security attributes before pushing to GitHub!

📝Independent Practice: Assignment

📄 course-catalog.html

University Department Course Catalog Object

•Create day-27/index.html with an array of 3 course objects.
•Each object must contain code, title, credits, and an instructor nested object.
•Use Object destructuring to extract course title and credits.
•Store and retrieve the array using JSON.stringify() and JSON.parse().

Submission Evaluation Criteria: Demonstrate proper object creation, nested access, and JSON stringification.

Exact Assignment Solution Code: course-catalog.html

Open Visual Studio Code on your PC (code .), create course-catalog.html, paste this complete step-by-step verified code, test in your browser, and push to your GitHub repo:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>BCA Day 27 - Objects & JSON Serialization</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: 'Segoe UI', Tahoma, sans-serif;
      background: #0b1120;
      color: white;
      min-height: 100vh;
      display: flex;
      justify-content: center;
      align-items: center;
      padding: 20px;
    }
    .catalog-card {
      background: #1e293b;
      border: 1px solid #334155;
      border-radius: 16px;
      padding: 28px;
      max-width: 520px;
      width: 100%;
    }
    h1 { font-size: 20px; color: #38bdf8; margin-bottom: 12px; }
    pre {
      background: #0f172a;
      padding: 14px;
      border-radius: 8px;
      font-size: 12px;
      color: #38bdf8;
      overflow-x: auto;
      max-height: 240px;
    }
  </style>
</head>
<body>
  <div class="catalog-card">
    <h1>BCA Department Course Catalog (JSON)</h1>
    <pre id="jsonPreview">Serializing catalog...</pre>
  </div>

  <script>
    // 1. Array of course objects with nested instructor object
    const courseCatalog = [
      {
        code: "BCS-011",
        title: "Computer Basics and PC Software",
        credits: 3,
        instructor: { name: "Er. Manoj Kumar", designation: "Lead Curriculum Architect" }
      },
      {
        code: "BCSL-013",
        title: "Software Lab (Linux & Web Basics)",
        credits: 2,
        instructor: { name: "Pankaj Sharma", designation: "Lab Instructor" }
      },
      {
        code: "BCS-012",
        title: "Basic Mathematics",
        credits: 4,
        instructor: { name: "Dr. Uday Verma", designation: "Mathematics Department" }
      }
    ];

    // 2. Object destructuring
    const [firstCourse] = courseCatalog;
    const { code, title, credits, instructor: { name } } = firstCourse;
    console.log(`Featured Course: ${code} - ${title} (${credits} Credits) by ${name}`);

    // 3. JSON Serialization & Local Storage
    const serialized = JSON.stringify(courseCatalog, null, 2);
    localStorage.setItem("bca_course_catalog", serialized);

    // 4. Retrieve and Parse
    const retrieved = JSON.parse(localStorage.getItem("bca_course_catalog"));
    console.log("Retrieved parsed count:", retrieved.length);

    document.getElementById("jsonPreview").textContent = serialized;
  </script>
</body>
</html>

Verified Assignment Code Solution (100% Tested & Ready to Run)

🎓4. Viva Check: Mandatory Conceptual Test

What is the standard purpose of JSON.stringify() in web applications?

5. Mandatory Step: Push to GitHub to Unlock Next Lesson

Target Repo: html-css-projects

Windows 11 Terminal / VS Code

mainhtml-css-projects

~/html-css-projects

mkdir day-27

Create a new project folder (day-27)

cd day-27

Change working directory to day-27

git checkout -b feature/day-27-objects

git add index.html

git commit -m "feat(day-27): add javascript objects and json serialization"

Commit staged changes with a descriptive message

git push origin feature/day-27-objects

Push local commits directly to your remote GitHub repository

⌨️ Paste into terminal:Ctrl + Vor right-click in Windows Terminal / VS Code✨ Word wrap active (no horizontal cutoff)

Completion Prerequisites VerificationIncomplete Steps

Google Login

✔ Required

VS Code Implementation

Step 4 Viva Check

Own GitHub Project

Required

Exact GitHub Setup Guide & Expected Structure

Day 27 Requirements

Follow these exact folder and file names to prevent verification errors.

1. GitHub Repository

html-css-projects

Must be set to Public

2. Exact FolderNEW

day-27/ or bca-day-27/

Create inside repo root

3. Exact File NameREQUIRED

index.html

⚠️ No spaces or custom names

4. What to Submit Below

https://github.com/YOU/html-css-projects

Or direct link to index.html

Terminal Commands to Create & Push Day 27

mainhtml-css-projects

# 1. Enter your repository directory

cd html-css-projects

Change working directory to html-css-projects

# 2. Create the exact folder for Day 27

mkdir day-27

Create a new project folder (day-27)

cd day-27

Change working directory to day-27

# 3. Create your code file: index.html

# (Write your Day 27 homework code inside index.html)

# 4. Save, stage, commit and push to GitHub:

git add .

Stage all modified files and new assets for commit

10$

git commit -m "Day 27: JavaScript Objects, Nested Data & JSON Serialization Basics"

Commit staged changes with a descriptive message

11$

git push origin main

Push local commits directly to your remote GitHub repository

⌨️ Paste into terminal:Ctrl + Vor right-click in Windows Terminal / VS Code✨ Word wrap active (no horizontal cutoff)

How to Avoid "Could not find your practical code file" Errors:

1.Use Lowercase index.html: Avoid spaces or custom names like Alan Turing..html or Index.HTML. Linux/GitHub servers are strictly case-sensitive.

2.Separate Day Folders: Create a new folder day-27/ for today so you don't overwrite previous days.

3.Ensure Public Visibility: If your GitHub repo is Private, automated validation cannot inspect your code. Set it to Public.

4.Check on GitHub Website: Before clicking "Verify", open your repo in Google Chrome to confirm your files were pushed to branch main.

📁 github.com/YOUR_USERNAME/html-css-projects

Branch: main

README.md# BCA Practical Portfolio overview

day-01/Day 1 Prior Lesson— HTML5 Boilerplate & First Webpage

└──index.html

day-02/Day 2 Prior Lesson— Heading Hierarchy & Text Formatting

└──index.html

day-03/Day 3 Prior Lesson— Hyperlinks & Accessible Images

└──index.html

day-04/Day 4 Prior Lesson— Lists & Navigation Menus

└──index.html

day-05/Day 5 Prior Lesson— Tables & Tabular Data Presentation

└──index.html

day-06/Day 6 Prior Lesson— Semantic HTML5 Layout

└──index.html

day-07/Day 7 Prior Lesson— HTML Forms & Input Controls

└──index.html

day-08/Day 8 Prior Lesson— HTML5 Form Validation & Regex

└──index.html

day-09/Day 9 Prior Lesson— HTML5 Media: Audio, Video & Embeds

└──index.html

day-10/Day 10 Prior Lesson— Sprint 1 Capstone: Developer Resume

└──index.html

└──styles.css

day-11/Day 11 Prior Lesson— CSS Box Model (Content, Padding, Border, Margin)

└──index.html

day-12/Day 12 Prior Lesson— CSS Display Modes & Document Flow

└──index.html

day-13/Day 13 Prior Lesson— CSS Positioning (Static, Relative, Absolute, Fixed, Sticky)

└──index.html

day-14/Day 14 Prior Lesson— Flexbox: 1D Layouts & Main Axis Alignment

└──index.html

day-15/Day 15 Prior Lesson— Flexbox: Cross Axis Alignment & Flex Items

└──index.html

day-16/Day 16 Prior Lesson— CSS Grid: 2D Layouts & Template Columns

└──index.html

day-17/Day 17 Prior Lesson— CSS Grid: Spanning & Grid Template Areas

└──index.html

day-18/Day 18 Prior Lesson— Responsive Design & Media Queries (Mobile-First)

└──index.html

day-19/Day 19 Prior Lesson— CSS Transitions & Micro-Interactions

└──index.html

day-20/Day 20 Prior Lesson— Sprint 2 Capstone: Responsive University Campus Portal

└──index.html

└──styles.css

day-21/Day 21 Prior Lesson— JavaScript Introduction: <script>, Variables & Types

└──index.html

day-22/Day 22 Prior Lesson— JavaScript Operators: Arithmetic & Strict Equality

└──index.html

day-23/Day 23 Prior Lesson— Control Flow: if-else if & switch Statements

└──index.html

day-24/Day 24 Prior Lesson— Loops & Iteration: for, while & for...of

└──index.html

day-25/Day 25 Prior Lesson— Functions: Declarations, Arrow Syntax & Scope

└──index.html

day-26/Day 26 Prior Lesson— Array Methods: push, map, filter & reduce

└──index.html

day-27/✨ CREATE THIS FOLDER FOR TODAY (Day 27)— Objects: Key-Value Pairs, Nested Data & JSON

└──index.htmlMust contain: { key: value }, JSON.stringify(), JSON.parse(), destructuring

Sequential Progression Enforced

You are welcome to read all notes, inspect code snippets, and practice all exercises of Day 27 freely! To officially submit your GitHub repository and unlock subsequent days in your portfolio, please complete Day 26: JavaScript Arrays & Modern Transformation Methods: push, map, filter & reduce first.

Complete Day 26 First

Day 26: JavaScript Arrays & Modern Transformation Methods: push, map, filter & reduce

Curriculum & Practical Systems Authored by Er. Manoj Kumar

NextSem Academy • BCA Practical Learning Portal

BCA Student Stories & UpdatesLive

JavaScript Objects, Nested Data & JSON Serialization Basics

Day 27 Step-by-Step Practical Flow

🎯1. What You Will Learn Today

JavaScript Objects, Nested Data & JSON Serialization Basics — Comprehensive Practical Guide

👨‍🏫3. Teacher Demonstration Code

2. Hands-On Practical Lab: Follow Instructions in VS Code

Day 27 Practical Task Test Studio

Spot the Bug: Accessing Undefined Nested Property Crash

Senior Developer Forensic Analysis:

📝Independent Practice: Assignment

University Department Course Catalog Object

🎓4. Viva Check: Mandatory Conceptual Test

5. Mandatory Step: Push to GitHub to Unlock Next Lesson

Exact GitHub Setup Guide & Expected Structure

Student Learning Dashboard

Guest Student

Computer Competency Test (CBT)100 MCQs

Practical Lesson UpdatesCoding Labs Only

Professional & Social IntegrationsPortfolio & Network