Debug

Debugging in chain is difficult, thus some functions are provided to help.

flow

Inject an inspector with inject.

WARNING

Do not modify data, or subsequent steps will be affected.

const inspector = <T>(args: { ok: true; data: T } | { ok: false; err: string }) => {
  console.log(args)
}

const userInfo = (await flow(ok(userId), andThen(queryUserInfo), inject(inspector), errThen(notify))).unwrap()

Output result of each step with log.

flow(ok(userId), log('INFO'), andThen(queryUserInfo), errThen(notify))

pipe

Inject an inspector with tap.

Apply an inspector to each item with peek.

WARNING

Do not modify the arguments of tap and peek.

pipe(
  [1, 2, 3, 4],
  map((v) => v + 1),
  tap((result) => console.log(result)), // log an iterator
  peek((item) => console.log(item)), // log 2, 3, 4, 5
  reduce((a, b) => a + b)
)