feat: add classes & inheritance

Author: ExploitEngineer

part6 (Object-Oriented Programming)/05_classes.js

@@ -1,7 +1,8 @@
 /*
-🔹 1. What Are Classes in JavaScript?
-JavaScript classes are syntactic sugar over the existing prototype-based inheritance. Classes make it easier to structure code using constructors, methods, and inheritance, following familiar OOP patterns like in Java, C++, etc.
+INFO: What Are Classes in JavaScript ?
+A class in Javascript is a way to create reusable blueprints for creating objects that share the same structure (properties) and behaviour (methods). It makes it easier to create & manage multiple similar objects.
 */
+
 class Person {
   constructor(name) {
     this.age = name;
@@ -20,8 +21,8 @@ class className {
     // setup
   }
 
-  method1() {}
-  method2() {}
+  method1() { }
+  method2() { }
 }
 
 class Animal {
@@ -210,8 +211,8 @@ console.log(person);
 what is instace: When you create an object using new, like new User(), that object is an instance of the class.
 Used to check if an object is an instance of a class or constructor.
 */
-class A {}
-class B extends A {}
+class A { }
+class B extends A { }
 
 let b = new B();
 console.log(b instanceof B); // true — b is instance of B

part6 (Object-Oriented Programming)/Classes_&_Inheritance.js/classes_&_inheritance.js

@@ -0,0 +1,117 @@
+/*
+INFO: What are classes in JavaScript ?
+A class in JavaScript is a way to create reusable blueprints for creating objects that share the same strcture (properties) and behavior (methods). It makes it easier to create and manage multiple similar objects.
+*/
+
+// This is blueprint (class) for making "Person" objects
+class Person {
+  constructor(name, age) {
+    this.name = name;
+    this.age = age;
+  }
+
+  greet() {
+    console.log(`Hello, my name is ${this.name}`);
+  }
+};
+
+// creating actual people (objects) from the blueprint
+const person1 = new Person("Alice", 25);
+const person2 = new Person("Bob", 30);
+
+person1.greet(); // Hello, my name is Alice
+
+/*
+1. constructor() is a special method that runs when an object is created.
+2. this refers to the new object being created.
+3. greet() is method that belongs to the class.
+*/
+
+/*
+INFO: Inheritance (Extending a Class)
+Inheritance allows one class to inherit from another class.
+*/
+
+// Example
+class User {
+  constructor(name) {
+    this.name = name;
+  }
+
+  speak() {
+    console.log(`${this.name} says hello.`);
+  }
+}
+
+class Developer extends User {
+  constructor(name, language) {
+    super(name); // calls the constructor of Person
+    this.language = language;
+  }
+
+  code() {
+    console.log(`${this.name} writes code in ${this.language}`);
+  }
+}
+
+const dev = new Developer("Rafay", "JavaScript");
+dev.speak(); // Rafay says hello.
+dev.code(); // Rafay writes code in JavaScript
+
+/*
+INFO: What is static in classes ?
+A static method or property belongs to the class itself, not to any object created from it.
+*/
+
+// Example
+class Car {
+  constructor(model) {
+    this.model = model;
+  }
+
+  static company() {
+    return "Toyota";
+  }
+}
+
+const myCar = new Car("BMW");
+
+console.log(Car.company()); // Toyota
+console.log(myCar.company()); // Error: myCar.company is not a function
+
+
+// INFO: get and set (Getters & Setters)
+
+/*
+INFO: What is getter ?
+A getter allows you to access a property like a variable, but it actually runs a fucntion behind the scenes.
+*/
+
+/*
+INFO: What is setter ?
+A setter allows you to control how a property is set (add validation, logs, etc.)
+*/
+
+class Employee {
+  constructor(name) {
+    this.name = name;
+  }
+
+  get name() {
+    return this._name.toUpperCase();
+  }
+
+  set name(value) {
+    if (value.length < 3) {
+      console.log("Name is too short!");
+      return;
+    }
+    this._name = value;
+  }
+}
+
+const emp = new Employee("rafay");
+console.log(emp.name); // RAFAY
+
+
+