* fix: stabilize validation and tests on Windows * test: add Windows smoke coverage for skill activation * refactor: make setup_web script CommonJS * fix: repair aegisops-ai frontmatter * docs: add when-to-use guidance to core skills * docs: add when-to-use guidance to Apify skills * docs: add when-to-use guidance to Google and Expo skills * docs: add when-to-use guidance to Makepad skills * docs: add when-to-use guidance to git workflow skills * docs: add when-to-use guidance to fp-ts skills * docs: add when-to-use guidance to Three.js skills * docs: add when-to-use guidance to n8n skills * docs: add when-to-use guidance to health analysis skills * docs: add when-to-use guidance to writing and review skills * meta: sync generated catalog metadata * docs: add when-to-use guidance to Robius skills * docs: add when-to-use guidance to review and workflow skills * docs: add when-to-use guidance to science and data skills * docs: add when-to-use guidance to tooling and automation skills * docs: add when-to-use guidance to remaining skills * fix: gate bundle helper execution in Windows activation * chore: drop generated artifacts from contributor PR * docs(maintenance): Record PR 457 sweep Document the open issue triage, PR supersedence decision, local verification, and source-only cleanup that prepared PR #457 for re-running CI. --------- Co-authored-by: sickn33 <sickn33@users.noreply.github.com>
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name, description, risk, source, version, tags
| name | description | risk | source | version | tags | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| fp-taskeither-ref | Quick reference for TaskEither. Use when user needs async error handling, API calls, or Promise-based operations that can fail. | unknown | community | 1.0.0 |
|
TaskEither Quick Reference
TaskEither = async operation that can fail. Like Promise<Either<E, A>>.
When to Use
- You need a quick fp-ts reference for async operations that can fail.
- The task involves API calls, Promise wrapping, or composing asynchronous error-handling pipelines.
- You want a concise cheat sheet for
TaskEitheroperators and patterns.
Create
import * as TE from 'fp-ts/TaskEither'
TE.right(value) // Async success
TE.left(error) // Async failure
TE.tryCatch(asyncFn, toError) // Promise → TaskEither
TE.fromEither(either) // Either → TaskEither
Transform
TE.map(fn) // Transform success value
TE.mapLeft(fn) // Transform error
TE.flatMap(fn) // Chain (fn returns TaskEither)
TE.orElse(fn) // Recover from error
Execute
// TaskEither is lazy - must call () to run
const result = await myTaskEither() // Either<E, A>
// Or pattern match
await pipe(
myTaskEither,
TE.match(
(err) => console.error(err),
(val) => console.log(val)
)
)()
Common Patterns
import { pipe } from 'fp-ts/function'
import * as TE from 'fp-ts/TaskEither'
// Wrap fetch
const fetchUser = (id: string) => TE.tryCatch(
() => fetch(`/api/users/${id}`).then(r => r.json()),
(e) => ({ type: 'NETWORK_ERROR', message: String(e) })
)
// Chain async calls
pipe(
fetchUser('123'),
TE.flatMap(user => fetchPosts(user.id)),
TE.map(posts => posts.length)
)
// Parallel calls
import { sequenceT } from 'fp-ts/Apply'
sequenceT(TE.ApplyPar)(
fetchUser('1'),
fetchPosts('1'),
fetchComments('1')
)
// With recovery
pipe(
fetchUser('123'),
TE.orElse(() => TE.right(defaultUser)),
TE.getOrElse(() => defaultUser)
)
vs async/await
// ❌ async/await - errors hidden
async function getUser(id: string) {
try {
const res = await fetch(`/api/users/${id}`)
return await res.json()
} catch (e) {
return null // Error info lost
}
}
// ✅ TaskEither - errors typed and composable
const getUser = (id: string) => pipe(
TE.tryCatch(() => fetch(`/api/users/${id}`), toNetworkError),
TE.flatMap(res => TE.tryCatch(() => res.json(), toParseError))
)
Use TaskEither when you need typed errors for async operations.