# RFC: choo v8 — same soul, modern engine

> Draft, to be posted as an issue on choojs/choo. Placeholders in
> [brackets]. Tone check before posting: continuation, not correction.

---

Hi everyone — long-time choo user, org member, still shipping things
with it. I'd like to propose (and have prototyped) a v8.

**The short version:** choo's design aged beautifully. The toolchain
around it didn't — browserify, the nanohtml transform, Babel 6, Travis.
v8 keeps the API and the philosophy and replaces every dead dependency
with either the platform or ~300 lines we own. I've built the whole
thing on a branch to make this a concrete conversation rather than a
wishlist: **[link to v8 branch]**.

## What stays exactly the same

The 7-line counter is still the 7-line counter. `choo()`, stores,
`emit`, tagged template views, morphing re-renders, `toString()` on the
server. `choo()` still works without `new`. A codemod
(`npx @choojs/migrate`) moves v7 apps across — validated against this
repo's own example app.

## What changes

- **ESM only, Node ≥ 24, Baseline browsers. Zero compile steps.** The
  nanohtml browserify transform is replaced by a runtime template cache
  (parse once per call site, clone per render — the µhtml technique,
  adapted to our morph-based model). Consequence: **you can develop a
  choo app with an import map and view-source**, no tooling at all.
- **Twelve packages become six.** nanobus/nanorouter/nanohref/nanotiming
  fold into `@choojs/core` as attributed ports; nanoquery/nanoraf/
  nanoassert retire to the platform. Smaller maintenance surface is the
  point — single-maintainer fatigue is what stalled v7, and I don't want
  to rebuild that failure mode.
- **SSR grows up: `toStream()`.** Web-standard `ReadableStream`,
  progressive flushing through async template holes, `state.prefetch`
  for store data, and hydration that *adopts* server DOM and warns on
  real mismatches. Answers the async-route question too — #653 finally
  gets both halves: `lazy(() => import('./view.js'))` in the browser,
  awaited by `toStream` on the server.
- **bankai v10** — same one-command soul, rebuilt as a thin shell over
  Vite 8/Rolldown. Only the client bundles (v8 server code runs
  as-authored — no server build to rot). 103 Early Hints replace the
  HTTP/2 push story, `style.css`/`sw.js` conventions replace sheetify
  and the env-var service-worker dance, `--prerender` and `--h2`
  included.
- **The size claim, honestly restated.** v7 said 4kb for choo alone
  (templates compiled away by the transform). v8's *entire* framework —
  core + html engine + morph + hydration — is 7.97 kB min+gzip
  / 7.15 kB brotli, enforced by CI. Apples-to-apples it's smaller;
  the README now says the true number.

Numbers, tests, and the full decision log live on the branch:
109 unit tests (the v7 suite among them, behavior preserved) + 7
Playwright tests in real Chromium covering hydration, streaming, and
bankai dev/prod. Also fixed along the way: the non-ASCII/`%` URL
crashes (routing now parses with WHATWG URL, decodes once, and
NFC-normalizes).

## What I'm asking

1. **@yoshuawuyts** — a blessing costs one emoji and would mean a lot.
   Zero obligation beyond that; the credits already say what this
   builds on.
2. **@pirxpilot** — your ESM fork line is the only living continuation
   of this code and v8's core started from that groundwork. I'd love to
   co-maintain rather than fork-in-parallel; either way, thank you.
3. **npm publish rights** for `choo`, `bankai`, and the nano*
   packages, or a nod to ship under `@choojs/*` with the old names as
   deprecation pointers after 8.0.0 exists (nothing gets deprecated
   before then; master and v7 stay untouched).
4. **API feedback**, especially: `lazy()` wrapper vs thenable route
   handlers; the `state.prefetch` contract; anything in the migration
   doc that reads as a betrayal rather than an upgrade.

**Comment window: three weeks from posting.** After that I'll take
silence as consent, keep working on the v8 branch in the open, and cut
pre-releases under a `next` tag. If this lands wrong for anyone, say so
— the plan bends.

🚂🚋🚋🚋🚋🚋