# bfirsh/jsnes

A JavaScript NES emulator.

Repository: https://github.com/bfirsh/jsnes
Canonical: https://ross.abutalabs.com/products/jsnes
Homepage: https://jsnes.org
Language: JavaScript
License: Apache-2.0
License Family: permissive
Topics: nes, emulation, javascript, emulator, 6502
Last push: 2026-08-25T06:24:06+00:00

## Health v2 (maintenance only)
Score: 88/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 66, longevity 100
- inputs: {"age_days": 6273, "days_push": 8, "days_rel": 144, "gap_med": 41, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 6414, forks 855 (observed 2026-08-28T04:09:43.270077+00:00)

## What it is
JSNES is a Nintendo Entertainment System (NES) emulator written in JavaScript, distributed as a library usable in both the browser and Node.js. It provides a high-level Browser component with rendering, audio, and input handling, plus a low-level NES class for custom integrations.

## Use cases
- embed a playable NES emulator in a web page
- run NES ROMs in Node.js
- build a React-based retro game player
- add gamepad and keyboard input to an emulator frontend
- render NES frames to a custom canvas or audio pipeline

## When to choose
- you want to emulate NES games in JavaScript without native dependencies
- you need a library-level emulator to embed in your own web app or React project
- you want headless emulation in Node.js with custom rendering or audio

## When to avoid
- you need to emulate consoles other than the NES
- you require cycle-accurate, high-fidelity emulation for serious preservation work
- you want a ready-made desktop emulator application

## Facets
- artifact type: library
- maturity: active
- function: game-engine, graphics, audio-processing, sdk
- domain: gaming-tools, web-development, frontend, cross-platform
- platform: browser, cross-platform
- tags: nes-emulator, emulation, 6502, retro-gaming, canvas, gamepad, react, nodejs, javascript

## Member repositories
- bfirsh/jsnes (main) score 88

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:43.270077+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 2026-08-29T17:44:55.298442+00:00, confidence not recorded.
  - readme: https://github.com/bfirsh/jsnes (fetched 2026-08-28T04:09:43.270077+00:00, sha 3b8bf53e03db)
  - homepage: https://jsnes.org (fetched 2026-08-29T08:42:00.383899+00:00, sha f4909a444992)
  - registry_npm: https://registry.npmjs.org/jsnes (fetched 2026-08-29T08:42:00.393757+00:00, sha 22b535618515)
- Data as of 2026-08-30T08:39:29.467469+00:00.