interface IScreen {
  setCallback(callback: Function);
  display(data: any);
}

class BasicOrderFlow {
  private screen: IScreen;

  private orderDetails = {
    vendorId: null,
    dishes: [],
    address: null,
    paymentType: null,
  };

  showScreen(newScreen: IScreen, callback: Function, data: any) {
    this.screen = newScreen;
    this.screen.setCallback(callback);
    this.screen.display(data);
  }

  /** Callback function passed to the vendor selection screen */
  selectVendorCb(vendorId: string) {
    // Validation
    if (!this.isValidVendorId(vendorId)) {
      console.warn('Invalid vendor ID:', vendorId);
      return;
    }

    // Execution
    this.orderDetails.vendorId = vendorId;

    // Transition
    this.showScreen(
      new SelectDishScreen(),
      dishes => this.selectDishCb(dishes),
      { vendorId },
    );
  }

  /** Callback function passed to the dish selection screen */
  selectDishCb(dishes: string[]) {
    // Etc...
  }
}