fp-interop

bun add @stopcock/fp @stopcock/fp-interop

fp-interop converts foreign tagged values and native JavaScript protocols at explicit boundaries. It has no runtime dependency on fp-ts, Effect, or another FP runtime; @stopcock/fp is its only peer.

import * as O from '@stopcock/fp/option'
import { fromOptionLike, toOptionLike } from '@stopcock/fp-interop/option-like'

const local = fromOptionLike(foreignOption, {
  read: (value) =>
    foreignIsSome(value) ? { _tag: 'Some', value: foreignValue(value) } : { _tag: 'None' },
})

const foreign = toOptionLike(O.some(42), {
  none: foreignNone,
  some: foreignSome,
})

Readers accept caller-supplied structural contracts. Converting back requires the foreign library’s real constructors, so the package never fabricates branded values. Tagged Option, Either, and non-empty Validation helpers cover the common fp-ts and Effect data shapes.

Other focused entries provide nullable and throwable boundaries, Promise, iterable and async-iterable conversion, direct Standard Schema delegation, validated JSON wire codecs, and Node callback adapters. Node-only helpers stay isolated in @stopcock/fp-interop/node; the root has no Node runtime import.

Public subpaths are option-like, either-like, boundary, standard-schema, wire, and node.