예시) 원격 restful 요청 + 에러핸들링

// 데이터를 요청하는 부분 
const httpGet = (url:string) => TE.tryCatch<Error, AxiosResponse>(
  () => axios.get(url),
  reason => new Error(String(reason))
)

//요청한 데이터를 decode 하는 코드
const getUser = pipe(
  httpGet('https://reqres.in/api/users?page=1'),
  TE.map(x => x.data),
  TE.chain((str) => pipe(
    users.decode(str), 
    E.mapLeft(err => new Error(String(err))), 
    TE.fromEither)
  )
);

import { pipe } from "fp-ts/lib/pipeable";
import * as E from "fp-ts/lib/Either";
import * as TE from "fp-ts/lib/TaskEither";

function getStuff(u: string): TE.TaskEither<Error, unknown> {
  return TE.tryCatch(
    () =>
      fetch(u).then(res => {
        if (!res.ok) {
          throw new Error(`fetch failed with status: ${res.status}`);
        }
        return res.json();
      }),
    E.toError
  );
}