factory.ts

interface Computer {
  run: () => void;
}

class Windows implements Computer {
  run() {
    console.log('Windows')
  }
}

class Mac implements Computer {
  run() {
    console.log('Mac')
  }
}

interface ComputerFactory {
  product: () => Computer;
}

class WindowsFactory implements ComputerFactory {
  product() {
    return new Windows()
  }
}

class MacFactory implements ComputerFactory {
  product() {
    return new Mac()
  }
}

const macFactory = new MacFactory()

const mac = macFactory.product()
mac.run()