Fp-ts-skills fp-pipe-ref

Quick reference for pipe and flow. Use when user needs to chain functions, compose operations, or build data pipelines in fp-ts.

install

source · Clone the upstream repo

git clone https://github.com/whatiskadudoing/fp-ts-skills

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/whatiskadudoing/fp-ts-skills "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/quick-ref/fp-pipe-ref" ~/.claude/skills/whatiskadudoing-fp-ts-skills-fp-pipe-ref && rm -rf "$T"

manifest: skills/quick-ref/fp-pipe-ref/SKILL.md

pipe & flow Quick Reference

pipe - Transform a Value

import { pipe } from 'fp-ts/function'

// pipe(startValue, fn1, fn2, fn3)
// = fn3(fn2(fn1(startValue)))

const result = pipe(
  '  hello world  ',
  s => s.trim(),
  s => s.toUpperCase(),
  s => s.split(' ')
)
// ['HELLO', 'WORLD']

flow - Create Reusable Pipeline

import { flow } from 'fp-ts/function'

// flow(fn1, fn2, fn3) returns a new function
const process = flow(
  (s: string) => s.trim(),
  s => s.toUpperCase(),
  s => s.split(' ')
)

process('  hello world  ') // ['HELLO', 'WORLD']
process('  foo bar  ')     // ['FOO', 'BAR']

When to Use

Use	When
`pipe`	Transform a specific value now
`flow`	Create reusable transformation

With fp-ts Types

import * as O from 'fp-ts/Option'
import * as A from 'fp-ts/Array'

// Option chain
pipe(
  O.fromNullable(user),
  O.map(u => u.email),
  O.getOrElse(() => 'no email')
)

// Array chain
pipe(
  users,
  A.filter(u => u.active),
  A.map(u => u.name)
)

Common Pattern

// Data last enables partial application
const getActiveNames = flow(
  A.filter((u: User) => u.active),
  A.map(u => u.name)
)

// Reuse anywhere
getActiveNames(users1)
getActiveNames(users2)