Backend_Structure/typescript-oops-tutorial.html at main · brijeshkrverma/Backend_Structure · GitHub

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<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>TypeScript OOPs Masterclass 🔥</title>
    <!-- Google Fonts -->
    <link rel="preconnect" href="https://fonts.googleapis.com">
    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
    <link
        href="https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500&display=swap"
        rel="stylesheet">
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    <script>hljs.highlightAll();</script>

    <style>
        :root {
            --bg-color: #0d1117; /* GitHub Darker */
            --surface-color: #161b22;
            --primary-color: #3178c6; /* TS Blue */
            --primary-glow: rgba(49, 120, 198, 0.4);
            --text-main: #f0f6fc;
            --text-muted: #8b949e;
            --border-color: rgba(255, 255, 255, 0.08);
            --card-border: rgba(255, 255, 255, 0.1);
            --accent-color: #f7df1e; /* JS Yellow */
            --warning-color: #ff7b72; /* Reddish for errors/rules */
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: 'Plus Jakarta Sans', sans-serif;
            background-color: var(--bg-color);
            color: var(--text-main);
            line-height: 1.6;
            background-image:
                radial-gradient(at 0% 0%, rgba(49, 120, 198, 0.15) 0px, transparent 50%),
                radial-gradient(at 100% 100%, rgba(139, 148, 158, 0.1) 0px, transparent 50%);
            background-attachment: fixed;
            min-height: 100vh;
        }

        .layout {
            display: flex;
            gap: 2.5rem;
            max-width: 1400px;
            margin: 0 auto;
            padding: 3rem 2rem;
            align-items: flex-start;
        }

        .sidebar {
            width: 280px;
            flex-shrink: 0;
            position: sticky;
            top: 3rem;
            max-height: calc(100vh - 6rem);
            overflow-y: auto;
            background: rgba(22, 27, 34, 0.8);
            border: 1px solid var(--card-border);
            border-radius: 16px;
            padding: 1.5rem;
            box-shadow: 0 20px 40px -20px rgba(0, 0, 0, 0.5);
            backdrop-filter: blur(12px);
        }

        .sidebar h3 {
            margin-top: 0;
            margin-bottom: 1rem;
            font-size: 1.1rem;
            text-transform: uppercase;
            letter-spacing: 1.5px;
            color: var(--primary-color);
            border-bottom: 1px solid var(--card-border);
            padding-bottom: 1rem;
        }

        .sidebar ul {
            list-style: none;
        }

        .sidebar li {
            margin-bottom: 0.3rem;
        }

        .nav-section {
            font-size: 0.85rem;
            text-transform: uppercase;
            letter-spacing: 1px;
            color: var(--text-muted);
            margin: 1.5rem 0 0.5rem 0;
            padding-left: 0.5rem;
            font-weight: 700;
        }

        .sidebar a {
            text-decoration: none;
            color: var(--text-muted);
            display: block;
            padding: 0.5rem 1rem;
            border-radius: 8px;
            transition: all 0.3s ease;
            font-size: 0.95rem;
            font-weight: 500;
        }

        .sidebar a:hover {
            background: rgba(49, 120, 198, 0.15);
            color: var(--primary-color);
            transform: translateX(5px);
        }

        .main-content {
            flex: 1;
            min-width: 0;
        }

        header {
            text-align: center;
            margin-bottom: 4rem;
        }

        h1 {
            font-size: 3rem;
            font-weight: 800;
            margin-bottom: 1rem;
            background: linear-gradient(135deg, #3178c6 0%, #38bdf8 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            text-shadow: 0 0 40px var(--primary-glow);
        }

        .subtitle {
            font-size: 1.2rem;
            color: var(--text-muted);
        }

        .section {
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            border: 1px solid var(--card-border);
            border-radius: 16px;
            padding: 2.5rem;
            margin-bottom: 2.5rem;
            box-shadow: 0 20px 40px -20px rgba(0, 0, 0, 0.5);
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            transition: transform 0.3s ease, box-shadow 0.3s ease;
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        .divider {
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            margin: 4rem 0;
            padding: 2rem 0;
            border-top: 1px dashed var(--card-border);
            border-bottom: 1px dashed var(--card-border);
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            color: var(--primary-color);
            margin: 0;
            font-size: 2rem;
            justify-content: center;
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        h2 {
            font-size: 1.8rem;
            margin-bottom: 1.5rem;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            color: #fff;
        }

        .main-content h3 {
            font-size: 1.3rem;
            margin: 1.5rem 0 1rem;
            color: #e2e8f0;
        }

        p {
            margin-bottom: 1rem;
            font-size: 1.1rem;
            color: #c9d1d9;
        }

        /* Callouts */
        .explanation {
            background: rgba(49, 120, 198, 0.1);
            border-left: 4px solid var(--primary-color);
            padding: 1rem 1.5rem;
            border-radius: 0 8px 8px 0;
            margin: 1.5rem 0;
        }

        .concept-explanation {
            background: rgba(247, 223, 30, 0.08); /* Yellowish JS vibe */
            border-left: 4px solid var(--accent-color);
            padding: 1rem 1.5rem;
            border-radius: 0 8px 8px 0;
            margin: 1.5rem 0;
        }

        .explanation p, .concept-explanation p {
            margin-bottom: 0;
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        }

        pre {
            background: #010409 !important;
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            border-radius: 12px;
            padding: 1.5rem !important;
            margin: 1.5rem 0;
            overflow-x: auto;
        }

        code {
            font-family: 'JetBrains Mono', monospace !important;
            font-size: 0.95rem;
        }

        /* Cards */
        .rule-card {
            background: linear-gradient(145deg, rgba(255, 123, 114, 0.1) 0%, rgba(220, 38, 38, 0.05) 100%);
            border: 1px solid rgba(255, 123, 114, 0.2);
            padding: 1.5rem;
            border-radius: 12px;
            margin-bottom: 1rem;
        }

        .rule-card h4 {
            color: var(--warning-color);
            margin-bottom: 0.5rem;
            font-size: 1.2rem;
        }

        .tip-card {
            background: linear-gradient(145deg, rgba(16, 185, 129, 0.1) 0%, rgba(5, 150, 105, 0.05) 100%);
            border: 1px solid rgba(16, 185, 129, 0.2);
            padding: 1.5rem;
            border-radius: 12px;
            margin-bottom: 1rem;
        }

        .tip-card h4 {
            color: #34d399; /* Emerald */
            margin-bottom: 0.5rem;
            font-size: 1.2rem;
        }

        hr {
            border: 0;
            height: 1px;
            background: var(--card-border);
            margin: 2rem 0;
        }

        .cta-banner {
            text-align: center;
            background: linear-gradient(135deg, #3178c6 0%, #8b5cf6 100%);
            padding: 3rem 2rem;
            border-radius: 16px;
            margin-top: 4rem;
        }

        .cta-banner h2 {
            justify-content: center;
            margin-bottom: 1rem;
        }

        .cta-banner p {
            color: rgba(255, 255, 255, 0.9);
            margin-bottom: 0;
        }

        .badge {
            background: var(--primary-color);
            color: #fff;
            padding: 0.2rem 0.6rem;
            border-radius: 6px;
            font-size: 0.8rem;
            font-weight: 700;
            vertical-align: middle;
            margin-left: 0.5rem;
        }

        .badge.yellow {
            background: var(--accent-color);
            color: #000;
        }

        ::-webkit-scrollbar {
            width: 8px;
            height: 8px;
        }

        ::-webkit-scrollbar-track {
            background: var(--bg-color);
        }

        ::-webkit-scrollbar-thumb {
            background: #30363d;
            border-radius: 4px;
        }

        ::-webkit-scrollbar-thumb:hover {
            background: var(--primary-color);
        }

        /* Responsive */
        @media (max-width: 900px) {
            .layout {
                flex-direction: column;
            }
            .sidebar {
                width: 100%;
                position: relative;
                top: 0;
                max-height: none;
                margin-bottom: 2rem;
            }
        }
    </style>
</head>

<body>

    <div class="layout">
        <!-- Sidebar Navigation -->
        <aside class="sidebar">
            <h3>📚 TS OOPs Guide</h3>
            <nav>
                <ul>
                    <li class="nav-section">Basics</li>
                    <li><a href="#intro-class">🏗️ Class & Object</a></li>
                    <li><a href="#constructor">🛠️ Constructor & `this`</a></li>

                    <li class="nav-section">Pillars of OOPs</li>
                    <li><a href="#encapsulation">🔒 Encapsulation (Access Modifiers)</a></li>
                    <li><a href="#inheritance">🧬 Inheritance</a></li>
                    <li><a href="#polymorphism">🎭 Polymorphism</a></li>
                    <li><a href="#abstraction">👻 Abstraction</a></li>

                    <li class="nav-section">Pro Features</li>
                    <li><a href="#readonly-getter">👀 Readonly & Getters/Setters</a></li>
                    <li><a href="#interfaces">📝 Interfaces (Contracts)</a></li>
                    <li><a href="#static">⚡ Static Properties</a></li>
                </ul>
            </nav>
        </aside>

        <!-- Main Content area -->
        <main class="main-content">
            <header>
                <h1>TypeScript OOPs Masterclass 🔥</h1>
                <p class="subtitle">Classes, Interfaces, aur Object-Oriented TS ka Poora Nuskha 🧑‍💻</p>
            </header>

            <!-- ==========================================
                 BASICS
            =========================================== -->

            <div class="section" id="intro-class">
                <h2>🏗️ 1. Class & Object (The Blueprints)</h2>
                <p><strong>Class:</strong> Ek naksha (blueprint) hota hai. (Jaise "Car" banane ka map).<br>
                <strong>Object:</strong> Us map se bani hui actual cheez! (Jaise tera "Swift" model).</p>
                <pre><code class="language-typescript">class Car {
  brand: string;   // Properties
  model: string;

  startEngine(): void { // Methods
    console.log("Vroom Vroom! 🏎️");
  }
}

// Object banana (Instantiate)
const myCar = new Car();
myCar.brand = "Toyota";
myCar.startEngine();</code></pre>
            </div>

            <div class="section" id="constructor">
                <h2>🛠️ 2. Constructor & `this` Keyword</h2>
                <p>Jab bhi Object banta hai, pehli baar koi cheez initialize karni ho, toh <code>constructor</code> chalata hai. <code>this</code> current object ko point karta hai.</p>
                <pre><code class="language-typescript">class User {
  name: string;
  age: number;

  constructor(userName: string, userAge: number) {
    this.name = userName;
    this.age = userAge;
    console.log(`${this.name} paida ho gya bhai! 🍼`);
  }
}

// Yahan automatically constructor chalega
const rohan = new User("Rohan", 25); </code></pre>
                <div class="tip-card">
                    <h4>💡 TS Shortcut (Parameter Properties)</h4>
                    <p>TS me properties upar likhne ki zarurat nahi. Constructor me direct access modifier daal de, TS khud handle kar lega:</p>
                    <pre style="margin-top: 10px; background: rgba(0,0,0,0.5) !important"><code class="language-typescript">class User {
  constructor(public name: string, public age: number) {}
}</code></pre>
                </div>
            </div>

            <!-- ==========================================
                 PILLARS
            =========================================== -->

            <div class="divider" id="encapsulation">
                <h2>🔒 ENCAPSULATION (Data Security)</h2>
                <p style="margin-top: 10px; color: var(--text-muted)">Koi bahar wala teri class ka data chhed na paaye!</p>
            </div>

            <div class="section">
                <h2>🛡️ 3. Access Modifiers</h2>
                <p>TypeScript mein 3 levels ki security/access hote hain:</p>
                <ul>
                    <li><strong style="color: #34d399">public</strong> (Default): Koi bhi kahin se bhi access kar le.</li>
                    <li><strong style="color: #fca5a5">private</strong>: Sirf class ke andar hi access hoga. (Bank Balance).</li>
                    <li><strong style="color: #fcd34d">protected</strong>: Class ke andar + uske baccho (Inherited classes) me access hoga.</li>
                </ul>

                <pre><code class="language-typescript">class BankAccount {
  public accountName: string;
  private balance: number; // Bahar se access nahi hoga!
  protected pinCode: number; // Sirf child class padh sakti hai

  constructor(name: string, amt: number) {
    this.accountName = name;
    this.balance = amt;
  }

  showBalance() {
    console.log(`Balance: $${this.balance}`); // Class ke andar allowed hai!
  }
}

const myAc = new BankAccount("Rohan", 5000);
// myAc.balance = 0; // 🛑 ERROR: Property 'balance' is private!</code></pre>
            </div>

            <div class="divider" id="inheritance">
                <h2>🧬 INHERITANCE (Baap - Beta Relation)</h2>
            </div>

            <div class="section">
                <h2>👶 4. Extending Classes (`extends`)</h2>
                <p>Code bar-bar likhne se bachne ke liye, ek class dusri Parent class ki properties "Inherit" (<kbd>extends</kbd>) karti hai.</p>

                <pre><code class="language-typescript">class Animal { // Parent Class
  constructor(public name: string) {}

  eat() { console.log(`${this.name} khana kha rha hai! 🍖`); }
}

class Dog extends Animal { // Child Class
  breed: string;

  constructor(name: string, breed: string) {
    super(name); // 'super' se parent ka constructor call hota hai (Zaruri h!)
    this.breed = breed;
  }

  bark() { console.log("Bhow Bhow! 🐕"); }
}

const tommy = new Dog("Tommy", "Pug");
tommy.eat();  // Parent wala method kaam aa gaya!
tommy.bark(); // Bachhe ka apna method</code></pre>

                <div class="rule-card">
                    <h4>✅ Rule of Inheritance:</h4>
                    <p>Agar tu child class me <code>constructor()</code> banata hai, toh pehli line me <code>super()</code> call karna <strong>Compulsory</strong> hai.</p>
                </div>
            </div>

            <div class="divider" id="polymorphism">
                <h2>🎭 POLYMORPHISM (Behrupiya)</h2>
            </div>

            <div class="section">
                <h2>🔄 5. Method Overriding</h2>
                <p>Jab Bachha (Child class), Baap (Parent class) ke same method ko apne style me <strong>re-define</strong> karta hai.</p>

                <pre><code class="language-typescript">class Employee {
  work() { console.log("Kaam kar raha hu..."); }
}

class Manager extends Employee {
  // Same method name, different behavior!
  work() {
    console.log("Employees par chilla raha hu! 🗣️");
  }
}

const mgr = new Manager();
mgr.work(); // Result: "Employees par chilla raha hu! 🗣️"</code></pre>
            </div>

            <div class="divider" id="abstraction">
                <h2>👻 ABSTRACTION (Details Chupana)</h2>
            </div>

            <div class="section">
                <h2>🌫️ 6. Abstract Classes</h2>
                <p>Aisi class jiska koi Direct Object nahi ban skta (Aadhi adhuri class). Ye dusrson ke liye sirf "Rulebook" hoti hai ki kya-kya fulfill karna hai.</p>

                <pre><code class="language-typescript">abstract class Shape {
  abstract calculateArea(): number; // Rule: Har shape ko ye method dena hi pdega!

  printDetails() {
    console.log("Main ek basic shape hu!"); // Concrete method (jo override zaruri nahi)
  }
}

// const s = new Shape(); // 🛑 ERROR: Cannot create an instance of abstract class

class Circle extends Shape {
  constructor(public radius: number) { super(); }

  // Majboori hai method implement karna:
  calculateArea(): number {
    return Math.PI * this.radius * this.radius;
  }
}</code></pre>
            </div>

            <!-- ==========================================
                 PRO FEATURES
            =========================================== -->

            <div class="divider" id="readonly-getter">
                <h2>💎 PRO FEATURES (TypeScript Magic)</h2>
            </div>

            <div class="section">
                <h2>👀 7. Readonly, Getters & Setters</h2>
                <p><strong><kbd>readonly</kbd>:</strong> Ek baar assign ho gaya, wapas change nahi hoga! (e.g. Aadhar Number).<br>
                <strong><kbd>get</kbd> & <kbd>set</kbd>:</strong> Custom logic run karna job bhi user property padhna ya set karna chahe.</p>

                <pre><code class="language-typescript">class UserProfile {
  readonly id: string = "USR_123";
  private _age: number = 18; // Convention: private variables start with "_"

  // GETTER: As a property padh sakte ho (function ki tarah call () ni karna pdta!)
  get myAge(): number {
    return this._age;
  }

  // SETTER: Value set karte time logic chala sakte hain
  set changeAge(newAge: number) {
    if(newAge < 0) throw new Error("Age minus me ni ho skti be!");
    this._age = newAge;
  }
}

const u = new UserProfile();
// u.id = "44"; // 🛑 ERROR: Cannot assign to 'id' because it is a read-only property.

u.changeAge = 25;   // Setter automatically trigger hoga (bina usko function ki tarah call kiye)
console.log(u.myAge); // Getter trigger! (Output: 25)</code></pre>
            </div>

            <div class="section" id="interfaces">
                <h2>📝 8. Interfaces (Data Contracts)</h2>
                <p>TypeScript mein Classes ek object ko structure dene ke liye <code>implements</code> keyword ka use kar sakti hain. Matlab ek guarantee contract sign karna padta hai.</p>

                <pre><code class="language-typescript">// Contract Document
interface Driveable {
  brand: string;
  start(): void;
}

// Class ko shart manni pdegi
class Truck implements Driveable {
  brand = "Tata";

  start() {
    console.log("Truck Start Hua, dhuk dhuk dhuk!");
  }
}</code></pre>
                <div class="concept-explanation">
                    <p>👉 <strong>Abstract Class vs Interface:</strong> Abstract class me tu logic + rules dono de sakta hai. Interface me sirf "Rules" rehte hain, logic nahi.</p>
                </div>
            </div>

            <div class="section" id="static">
                <h2>⚡ 9. Static Properties & Methods</h2>
                <p>Normal properties Class <strong>ke object</strong> par lagti hain (`const x = new Math; x.calculate()`).<br>
                <strong><kbd>static</kbd></strong> properties <strong>Direct Class</strong> par lagti hain (Bina object banaye!).</p>

                <pre><code class="language-typescript">class DatabaseConf {
  // Bina 'new DatabaseConf()' chalaye kaam karega:
  static url: string = "mongodb://localhost:27017";

  static connect() {
    console.log(`Connecting to ${this.url}...`);
  }
}

// See? Sidha Class Name se bula rhe hain:
console.log(DatabaseConf.url);
DatabaseConf.connect();</code></pre>
            </div>

            <div class="cta-banner">
                <h2>TS OOPs Mastery Completed! 🎉</h2>
                <p>Ab tu Java/Angular developers ke sath aaram se level match karke baat kar sakta hai. Ab classes deke thara bhai darne wala nahi hai! <br><br>
                    <strong>Keep Crushing The Code! 💻🔥</strong>
                </p>
            </div>
        </main>
    </div>

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