Handle error with TypeScript

errorHandlingWithTS.ts

interface Pokemon {
  id: number;
  name: string;
  height: number;
  types: { id: number; name: string }[];
}

type GetPokemonSuccessResult = { isOk: true; data: Pokemon; error: null };
type GetPokemonErrorResult = { isOk: false; data: null; error: string };
type GetPokemonResult = GetPokemonSuccessResult | GetPokemonErrorResult;

function getPokemon(): GetPokemonResult {
  if (Math.random() > 0.5) {
    return {
      isOk: true,
      data: {
        id: 1,
        name: "pokemon 1",
        height: 137,
        types: [{ id: 1, name: "type 1" }],
      },
      error: null,
    };
  } else {
    return {
      isOk: false,
      data: null,
      error: "Some error happened",
    };
  }
}

function handleApiCall() {
  const { isOk, data, error } = getPokemon();

  if (isOk) {
    console.log(data);
  } else {
    console.log(error);
  }
}