playing around with Effect/io

http.ts

import { pipe } from '@fp-ts/data/Function';
import * as E from '@fp-ts/data/Either';
import * as Effect from '@effect/io/Effect';
// import * as Layer from '@effect/io/Layer';
// import * as Context from '@fp-ts/data/Context';
import { z } from 'zod';
import debug_ from 'debug';

export function decode<T>(schema: z.ZodSchema<T>) {
  return (input: unknown): E.Either<z.ZodError<T>, T> => {
    const result = schema.safeParse(input);
    if (result.success) {
      return E.right(result.data);
    } else {
      return E.left(result.error);
    }
  };
}

export const debug =
  (namespace: string) =>
  (formatter: any, ...args: any[]) =>
    Effect.sync(() => {
      debug_(namespace)(formatter, ...args);
    });

export const httpDebug = debug('http');

export const GetJson = (url: string, schema: z.Schema) =>
  pipe(
    Effect.tryCatchPromise(
      () => fetch(url),
      err => E.left({ message: 'fetch failed', err }),
    ),
    Effect.flatMap(res =>
      Effect.tryCatchPromise(
        () => res.json(),
        err => E.left({ message: 'json parse failed', err }),
      ),
    ),
    Effect.map(decode(schema)),
    Effect.flatMap(Effect.fromEither),
    Effect.flatMap(r => httpDebug('%O', r)),
  );

export const GetJsonGen = (url: string, schema: z.Schema) =>
  Effect.gen(function* ($) {
    const res = yield* $(
      Effect.tryCatchPromise(
        () => fetch(url),
        err => E.left({ message: 'fetch failed', err }),
      ),
    );

    const json = yield* $(
      Effect.tryCatchPromise(
        () => res.json(),
        err => E.left({ message: 'json parse failed', err }),
      ),
    );

    const result = yield* $(pipe(json, decode(schema), Effect.fromEither));

    // yield* $(httpDebug('%O', result));

    // dal momento che siamo dentro un generatore possiamo anche chiamare il
    // codice sincrono... un bene o un male:?
    debug_('http')('%O', result);
  });

const GistsSchema = z.array(
  z.object({ id: z.string(), description: z.string().nullable() }),
);

const program = GetJsonGen('https://api.github.com/gists', GistsSchema);

Effect.unsafeFork(program);