# marpple/FxTS

A functional programming library for TypeScript/JavaScript

Repository: https://github.com/marpple/FxTS
Canonical: https://ross.abutalabs.com/products/fxts
Homepage: https://fxts.dev
Language: TypeScript
License: Apache-2.0
License Family: permissive
Topics: fp, typescript, lazy, concurrency, javascript
Last push: 2026-08-29T03:47:12+00:00

## Health v2 (maintenance only)
Score: 99/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 100, release rhythm 96, longevity 100
- inputs: {"age_days": 1798, "days_push": 4, "days_rel": 25, "gap_med": 16.0, "n_releases_24m": 27}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1167, forks 87 (observed 2026-09-01T02:14:03.947740+00:00)

## What it is
FxTS is a functional programming library for TypeScript and JavaScript built on Iterable/AsyncIterable protocols. It provides lazy evaluation, composable pipe-based data transformation, and concurrency control for async operations with strong type inference.

## Use cases
- process large or infinite sequences lazily without loading everything into memory
- compose map/filter/reduce pipelines with pipe and strong type inference
- control concurrency of async requests with backpressure
- write declarative functional code in TypeScript
- terminate async work early with take over AsyncIterables

## When to choose
- you want lazy evaluation and AsyncIterable pipelines beyond what lodash or native iterator helpers offer
- you need curried, data-last function composition with excellent TypeScript inference
- you need to throttle concurrent async requests with backpressure

## When to avoid
- you need a batteries-included utility belt with deep object manipulation like lodash
- your project cannot enable strict TypeScript compiler options
- you target environments without ES2018+ support and cannot use polyfills

## Facets
- artifact type: library
- maturity: active
- function: concurrency, serialization
- domain: web-development, frontend, backend, developer-tools
- platform: browser, cross-platform
- tags: functional-programming, lazy-evaluation, iterables, async-iterables, pipe, type-inference, data-last-composition, nodejs, typescript

## Member repositories
- marpple/FxTS (main) score 99

## Provenance
- Observed fields: from GitHub, fetched 2026-09-01T02:14:03.947740+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:28:59.556504+00:00, confidence not recorded.
  - readme: https://github.com/marpple/FxTS (fetched 2026-09-01T02:14:03.947740+00:00, sha 65a01db22a83)
  - homepage: https://fxts.dev (fetched 2026-08-29T12:35:19.516600+00:00, sha 07a0d6a87807)
  - site_page: https://fxts.dev/guide/getting-started (fetched 2026-08-29T12:35:19.525628+00:00, sha 8ed236973feb)
  - site_page: https://fxts.dev/api (fetched 2026-08-29T12:35:19.527556+00:00, sha 11c635a061a8)
- Data as of 2026-08-30T08:39:29.467469+00:00.