# facebookarchive/rebound-js

Spring dynamics in JavaScript.

Repository: https://github.com/facebookarchive/rebound-js
Canonical: https://ross.abutalabs.com/products/rebound-js
Language: JavaScript
License: NOASSERTION
License Family: other
Archived: true
Last push: 2020-12-11T03:28:07+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 8, longevity 100
- inputs: {"age_days": 4422, "days_push": 2091, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: archived, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1744, forks 124 (observed 2026-08-28T04:05:30.555382+00:00)

## What it is
Rebound-js is a JavaScript library that models spring dynamics for driving physical animations in web interfaces. It provides a SpringSystem that iterates Spring objects through a physics solver until equilibrium, letting developers map position updates to UI property animations.

## Use cases
- add springy bounce animations to web UI elements
- animate scale, translation, or rotation with physics-based motion
- create press-and-release interactive effects on buttons and logos
- drive interface animations from a lightweight physics simulation
- port Android-style spring animations to the web

## When to choose
- you want natural, physics-based spring animations without a full animation framework
- you need a small, dependency-free library for bouncy UI interactions
- you want consistent spring behavior matching Facebook's Android Rebound library

## When to avoid
- you need a full-featured animation library with timelines, keyframes, and easing
- you require actively maintained software with ongoing support
- you need GPU-accelerated or CSS-only animation solutions

## Facets
- artifact type: library
- maturity: maintenance
- function: animation
- domain: web-development, frontend
- platform: browser, cross-platform
- tags: spring-dynamics, physics-animation, javascript, facebook-archive, nodejs

## Member repositories
- facebookarchive/rebound-js (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:30.555382+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 2026-08-30T03:29:26.882015+00:00, confidence not recorded.
  - readme: https://github.com/facebookarchive/rebound-js (fetched 2026-08-28T04:05:30.555382+00:00, sha 9f51108aaa89)
- Data as of 2026-08-30T08:39:29.467469+00:00.