index.ts

abstract class AbstractClass {
  public templateMethod(): void {
    this.baseOperation1();
    this.requiredOperations1();
    this.baseOperation2();
    this.hook1();
    this.requiredOperation2();
    this.baseOperation3();
    this.hook2();
  }

  protected baseOperation1(): void {
    console.log('AbstractClass says: I am doing the bulk of the work');
  }

  protected baseOperation2(): void {
    console.log('AbstractClass says: But I let subclasses override some operations');
  }

  protected baseOperation3(): void {
    console.log('AbstractClass says: But I am doing the bulk of the work anyway');
  }

  protected abstract requiredOperations1(): void;

  protected abstract requiredOperation2(): void;

  protected hook1(): void { }

  protected hook2(): void { }
}

class ConcreteClass1 extends AbstractClass {
  protected requiredOperations1(): void {
    console.log('ConcreteClass1 says: Implemented Operation1');
  }

  protected requiredOperation2(): void {
    console.log('ConcreteClass1 says: Implemented Operation2');
  }
}

class ConcreteClass2 extends AbstractClass {
  protected requiredOperations1(): void {
    console.log('ConcreteClass2 says: Implemented Operation1');
  }

  protected requiredOperation2(): void {
    console.log('ConcreteClass2 says: Implemented Operation2');
  }

  protected hook1(): void {
    console.log('ConcreteClass2 says: Overridden Hook1');
  }
}

function clientCodeContext() {
  console.log('Same client code can work with different subclasses:');
  new ConcreteClass1().templateMethod()
  console.log('');

  console.log('Same client code can work with different subclasses:');
  new ConcreteClass2().templateMethod()
}

export function templateMethod() {
  clientCodeContext()
}