From antigravity-awesome-skills
Quick reference for fp-ts types. Use when user asks which type to use, needs Option/Either/Task decision help, or wants fp-ts imports.
npx claudepluginhub absjaded/antigravity-awesome-skillsThis skill uses the workspace's default tool permissions.
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Verifies tests pass on completed feature branch, presents options to merge locally, create GitHub PR, keep as-is or discard; executes choice and cleans up worktree.
Guides root cause investigation for bugs, test failures, unexpected behavior, performance issues, and build failures before proposing fixes.
Writes implementation plans from specs for multi-step tasks, mapping files and breaking into TDD bite-sized steps before coding.
Is the operation async?
├─ NO: Does it involve errors?
│ ├─ YES → Either<Error, Value>
│ └─ NO: Might value be missing?
│ ├─ YES → Option<Value>
│ └─ NO → Just use the value
└─ YES: Does it involve errors?
├─ YES → TaskEither<Error, Value>
└─ NO: Might value be missing?
├─ YES → TaskOption<Value>
└─ NO → Task<Value>
// Core
import { pipe, flow } from 'fp-ts/function'
// Types
import * as O from 'fp-ts/Option' // Maybe exists
import * as E from 'fp-ts/Either' // Success or failure
import * as TE from 'fp-ts/TaskEither' // Async + failure
import * as T from 'fp-ts/Task' // Async (no failure)
import * as A from 'fp-ts/Array' // Array utilities
| Need | Code |
|---|---|
| Wrap nullable | O.fromNullable(value) |
| Default value | O.getOrElse(() => default) |
| Transform if exists | O.map(fn) |
| Chain optionals | O.flatMap(fn) |
| Wrap try/catch | E.tryCatch(() => risky(), toError) |
| Wrap async | TE.tryCatch(() => fetch(url), toError) |
| Run pipe | pipe(value, fn1, fn2, fn3) |
// Option
pipe(maybe, O.match(
() => 'nothing',
(val) => `got ${val}`
))
// Either
pipe(result, E.match(
(err) => `error: ${err}`,
(val) => `success: ${val}`
))