ArrowJS

Why it's ranked here

The pitch is specific: stick to modules, template literals and the page's own object model, so a coding agent writes it correctly without learning a compiler or a custom file format. The repository backs that with an installer that teaches Codex or Claude the framework, a one-line app scaffolder, and a WebAssembly sandbox for untrusted generated components. It is MIT licensed and its continuous integration typechecks, tests and builds on every push. The performance notes are candid that it still trails Solid and Vue on first render.

What's good

The core surface is small: components, templates, reactive state, a watcher, cleanup and a next-tick helper, most with one-letter aliases. Server rendering and hydration are layered on the same component model rather than a second API. Hydration is forgiving: it tries to adopt existing server markup, falls back to swapping only marked regions, and replaces the whole subtree as a last resort, reporting each mismatch through a callback. The performance plan bans benchmark-only shortcuts and measures against the standard framework benchmark suite.

Tradeoffs

By the project's own published measurements, creating a thousand rows took about 42 ms against about 32 ms for Solid, and non-keyed partial updates were more than twice as slow as keyed ones. The plan calls create cost the main remaining gap. Async components need the framework, server or hydration layer imported before rendering, a load-order rule that is easy to miss. The scaffolder assumes Vite, and the sandbox, compiler and Vite plugin are only partly visible from the files read.

How to use it well

Reach for it when agents generate interface code and you want output that runs straight in a browser module import, or when you need to render agent-written components in isolation from the host page. Start with the core package alone and add the server layers only when you need them. Prefer keyed lists for data that updates often. Teams chasing top benchmark numbers on large initial renders, or needing a mature component ecosystem, are better served elsewhere.

Observed

License

MIT

Language

TypeScript

Packaging

pnpm monorepo publishing separate npm packages for core, framework, SSR, hydration and sandbox

Install surface

npm package, create-arrow-js scaffolder, npx agent-skill installer, browser ESM import

Interfaces

JavaScript library; CLI scaffolder; CLI skill installer for Codex and Claude

Sandbox

QuickJS compiled to WebAssembly, rendering into the host DOM

Testing

Vitest with jsdom for unit specs; Playwright for end-to-end

CI

Typecheck, test and build run on every push