# rvagg/through2

Tiny wrapper around Node streams2 Transform to avoid explicit subclassing noise

Repository: https://github.com/rvagg/through2
Canonical: https://ross.abutalabs.com/products/through2
Language: JavaScript
License: MIT
License Family: permissive
Last push: 2026-08-25T01:54:10+00:00

## Health v2 (maintenance only)
Score: 98/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 95, longevity 100
- inputs: {"age_days": 4780, "days_push": 9, "days_rel": 34, "gap_med": 1, "n_releases_24m": 12}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1907, forks 105 (observed 2026-08-28T04:05:52.596933+00:00)

## What it is
A tiny Node.js library that wraps stream Transform logic in simple functions, avoiding explicit subclassing of stream.Transform. It supports both Node-style streams and Web Streams pipelines with callback, async function, and async generator transform styles.

## Use cases
- transform data chunks in a node.js stream pipeline without writing a Transform subclass
- map filter or batch items flowing through a stream
- insert async transformation logic into a web streams pipeThrough pipeline
- parse newline-delimited input line by line from a readable stream
- build object-mode transform streams with minimal boilerplate

## When to choose
- you need to add transformation steps to Node.js or Web Streams pipelines with minimal code
- you want to avoid subclassing stream.Transform and handling backpressure manually
- you prefer a tiny dependency with a simple function-based API
- you need async/await or async generator support in stream transforms

## When to avoid
- you need complex multi-stage stream orchestration beyond simple transforms
- you are not working with streams at all
- you require CommonJS on Node versions older than 22.12 without pinning to v4

## Facets
- artifact type: library
- maturity: stable
- function: streaming, concurrency, developer-tools
- domain: developer-tools, backend
- platform: -
- tags: node-streams, web-streams, transform-stream, stream-pipeline, esm, data-engineering, nodejs, javascript

## Member repositories
- rvagg/through2 (main) score 98

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:52.596933+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 2026-08-30T03:11:16.164358+00:00, confidence not recorded.
  - readme: https://github.com/rvagg/through2 (fetched 2026-08-28T04:05:52.596933+00:00, sha 786c5cd22f9c)
  - registry_npm: https://registry.npmjs.org/through2 (fetched 2026-08-29T10:50:46.461234+00:00, sha 833e313b1703)
- Data as of 2026-08-30T08:39:29.467469+00:00.