Phantom Builder in TS

Chief_n_Pizza.ts

// Inspired by https://medium.com/@maximilianofelice/builder-pattern-in-scala-with-phantom-types-3e29a167e863

export type Pizza = {};

namespace Pizza {
  export type WithCheese = {
    readonly cheese: string;
  };
  export type WithTopping = {
    readonly topping: string;
  };
  export type WithDough = {
    readonly dough: 'white' | 'black';
  };
  export type Full = WithCheese & WithTopping & WithDough;
}

class Chief<T extends Pizza> {
  constructor(
    readonly pizza: T,
  ) {}

  addCheese(cheeseType: string): Chief<T & Pizza.WithCheese> {
    return new Chief(Object.assign({}, this.pizza, {
      cheese: cheeseType,
    }));
  }

  addTopping(toppingType: string): Chief<T & Pizza.WithTopping> {
    return new Chief(Object.assign({}, this.pizza, {
      topping: toppingType,
    }));
  }

  addDough(doughType: 'white' | 'black'): Chief<T & Pizza.WithDough> {
    return new Chief(Object.assign({}, this.pizza, {
      dough: doughType,
    }));
  }

  static startPizza(): Chief<Pizza> {
    return new Chief({});
  }
}

class Oven {
  cookPizza(pizza: Pizza.Full): void {

  }
}


const pizzaToCook = Chief.startPizza() // note that if one of these steps is missing, oven will not cook a pizza
  .addCheese('Cheddar')
  .addDough('white')
  .addTopping('Pickle')
  .pizza;

new Oven().cookPizza(pizzaToCook);