AntiPattern - Practically may seem useful at first, but leads to issues in the long run.They are counterproductive and should be avoided.

• Classic Patterns
  • Typically around OOPS solution.
  • Creational
  • Structural
  • Behavioral.

• Creational Design Patterns They aim to solve the problems associated with creating objects in a way that enhances flexibility and reuse of existing code. The primary purpose of creational patterns is to separate the logic of object creation from the rest of the code

  1. Singleton - Ensures a class has only one instance and provides a global point of access to it.

       class Singleton {
      private static instance: Singleton;
     
      private constructor() {}
     
      public static getInstance(): Singleton {
          if (!Singleton.instance) {
              Singleton.instance = new Singleton();
          }
          return Singleton.instance;
      }
       }
       const singleton1 = Singleton.getInstance();
       const singleton2 = Singleton.getInstance();
       console.log(singleton1 === singleton2); // true
     

  2. Factory Method - Defines an interface for creating an object, but lets subclasses alter the type of objects that will be created. ```ts interface Product { operation(): string; }
     class ConcreteProductA implements Product { public operation(): string { return ‘Result of ConcreteProductA’; } } class ConcreteProductB implements Product { public operation(): string { return ‘Result of ConcreteProductB’; } } abstract class Creator { public abstract factoryMethod(): Product; public someOperation(): string { const product = this.factoryMethod(); return Creator: The same creator's code has just worked with ${product.operation()}; }

  } class ConcreteCreatorA extends Creator { public factoryMethod(): Product {
  return new ConcreteProductA(); } } class ConcreteCreatorB extends Creator { public factoryMethod(): Product {
  return new ConcreteProductB(); } } // Usage const creatorA = new ConcreteCreatorA(); console.log(creatorA.someOperation());
  const creatorB = new ConcreteCreatorB(); console.log(creatorB.someOperation());
  ```