ProductB.ts

export interface AbstractProductB {
  usefulFunctionB(): string;
}

export class ConcreteProductB1 implements AbstractProductB {
  public usefulFunctionB(): string {
    return "The result of the product B1.";
  }
}

export class ConcreteProductB2 implements AbstractProductB {
  public usefulFunctionB(): string {
    return "The result of the product B2.";
  }
}