# kolodny/immutability-helper

mutate a copy of data without changing the original source

Repository: https://github.com/kolodny/immutability-helper
Canonical: https://ross.abutalabs.com/products/immutability-helper
Language: TypeScript
License: MIT
License Family: permissive
Last push: 2020-10-15T13:51:46+00:00

## Health v2 (maintenance only)
Score: 23/100 (v2, computed 2026-09-03T02:39:23.370411+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 3843, "days_push": 2148, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5184, forks 185 (observed 2026-08-28T04:09:11.840365+00:00)

## What it is
A small TypeScript/JavaScript library that lets you apply mutations ($push, $set, $merge, etc.) to a copy of your data while leaving the original untouched. It is a drop-in replacement for React's deprecated react-addons-update and is commonly used for immutable state updates in React apps.

## Use cases
- update nested state immutably in React
- replace deep-copy boilerplate when changing nested objects
- push items to an array without mutating the original
- implement fast shouldComponentUpdate with immutable data
- migrate from react-addons-update
- merge objects into nested state without side effects

## When to choose
- you need lightweight immutable updates without changing your data representation
- you want a drop-in replacement for react-addons-update
- you use React and want cheap reference-equality change detection
- you find Immutable.js too heavy or want plain JS objects

## When to avoid
- you want persistent data structures with structural sharing (use Immutable.js)
- you use Immer's produce-style drafts and prefer that API
- your project needs active development and frequent releases
- you need deep immutability enforcement rather than copy-on-write helpers

## Facets
- artifact type: library
- maturity: maintenance
- function: serialization
- domain: developer-tools, frontend, web-development
- platform: browser, cross-platform
- tags: immutability, immutable-data, state-management, react, typescript, javascript, nodejs

## Member repositories
- kolodny/immutability-helper (main) score 23

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:11.840365+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 2026-08-29T18:01:47.133172+00:00, confidence not recorded.
  - readme: https://github.com/kolodny/immutability-helper (fetched 2026-08-28T04:09:11.840365+00:00, sha d14c28a8dfca)
  - registry_npm: https://registry.npmjs.org/immutability-helper (fetched 2026-08-29T08:55:49.398560+00:00, sha 60955b42aa8b)
- Data as of 2026-08-30T08:39:29.467469+00:00.