Challenge #1

houses.json

[
  { "name": "Atreides", "planets": "Calladan" },
  { "name": "Corrino", "planets": ["Kaitan", "Salusa Secundus"] },
  { "name": "Harkonnen", "planets": ["Giedi Prime", "Arrakis"] }
]

interfaces.ts

interface House {
...
}

interface HouseWithID {
...
}

function findHouses(houses: string): HouseWithID[];
function findHouses(
  houses: string,
  filter: (house: House) => boolean
): HouseWithID[];
function findHouses(houses: House[]): HouseWithID[];
function findHouses(
  houses: House[],
  filter: (house: House) => boolean
): HouseWithID[];

console.log(
  findHouses(JSON.stringify(houses), ({ name }) => name === "Atreides")
);

console.log(findHouses(houses, ({ name }) => name === "Harkonnen"));

import houses from "./houses.json";

interface House {
  name: string;
  planets: string | string[];
}

interface HouseWithID {
  id: number;
  house: House;
}

type FilterFunc = (house: House) => boolean;

function findHouses(houses: string): HouseWithID[];
function findHouses(houses: string, filter: FilterFunc): HouseWithID[];
function findHouses(houses: House[]): HouseWithID[];
function findHouses(houses: House[], filter: FilterFunc): HouseWithID[];

function findHouses(houses: unknown, filter?: unknown): HouseWithID[] {
  let housesWithID: HouseWithID[] = (
    typeof houses === "string" ? JSON.parse(houses) : houses
  ).map((house: House, index: number) => ({
    house,
    id: index + 1,
  }));

  if (typeof filter === "function") {
    housesWithID = housesWithID.filter((house: HouseWithID) =>
      (filter as FilterFunc)(house.house)
    );
  }

  return housesWithID;
}

console.log(findHouses(JSON.stringify(houses)));

console.log(
  findHouses(JSON.stringify(houses), ({ name }) => name === "Atreides")
);

console.log(findHouses(houses, ({ name }) => name === "Harkonnen"));