How to write an async class constructor using functional options pattern

options_functional_async.ts

type Material = 'wood' | 'brick' | 'steel'

type HouseOption = (h: House) => void

class House {
  private rooms: number
  private floors: number
  private material: Material
  private externalData: any

  constructor(...options: HouseOption[]) {
    // defaults
    this.rooms = 1
    this.floors = 1
    this.material = 'wood'
    this.externalData = null
    
    // set the options
    for (const option of options) {
      option(this)
    }
  }

  public static WithRooms(roomCount: number): HouseOption {
    return (h: House): void => {
      h.rooms = roomCount
    }
  }

  public static WithFloors(floorCount: number): HouseOption {
    return (h: House): void => {
      h.floors = floorCount
    }
  }

  public static WithMaterial(material: Material): HouseOption {
    return (h: House): void => {
      h.material = material
    }
  }

  public static async WithExternalData(): Promise<HouseOption> {
    // fetch the external data here (this is just a demonstration, could be any async op)
    const data = await externalAPI.getData()
    // now set the data on the class instance
    return (h: House): void => {
      h.externalData = data
    }
  }
}

constructor:

const myHouse = new House(
  House.WithRooms(5),
  House.WithFloors(2),
  House.WithMaterial('wood'),
  await House.WithExternalData(),
)