Functional isometric-fetch

fp-ts-fetch.ts

import fetch from 'isomorphic-unfetch';
import { pipe } from 'fp-ts/lib/function';
import * as TE from 'fp-ts/lib/TaskEither';
import * as E from 'fp-ts/lib/Either';
import * as O from 'fp-ts/lib/Option';

export const url = 'https://swapi.dev/api/planets/1/';

export const log = <A>(x: A) => {
  console.info(x);
  return x;
};

export type ThingWithAName = {
  readonly name: string;
  readonly rotation_period: string;
};

export const safeJson = <T = unknown>(
  resp: Response
): TE.TaskEither<Error, T> =>
  TE.tryCatch(
    () => resp.json(),
    (reason) => new Error(String(reason))
  );

(async () => {
  const initialFetch = pipe(
    TE.tryCatch(
      () => fetch(url),
      () => O.none
    ),
    TE.chain((resp) =>
      TE.tryCatch(
        (): Promise<ThingWithAName> => resp.json(),
        () => O.some('Failed to read json from response')
      )
    )
  );

  const data = pipe(
    await initialFetch(),
    E.getOrElseW(() => Error('Data Failed'))
  );

  console.log(data);
})();