buuh/docs/v8.md

choo v8 — branch notes

This branch is the working tree for the v8 modernization effort. The v7 code at the repo root is untouched and stays authoritative until 8.0.0 ships; everything new lives under packages/.

Layout

• packages/core — @choojs/core: the Choo class, same API as choo v7 (use/route/start/mount/toString/emit), ported to ESM. The nano* internals are consolidated into lib/ as attributed ports:
  • lib/bus.js ← nanobus 4.5.0
  • lib/router.js ← nanorouter 4.0.0 + wayfarer 7.0.1 (+ trie)
  • lib/cache.js ← choo component/cache.js + nanolru 1.0.0
  • lib/raf.js ← nanoraf 3.1.0, lib/href.js ← nanohref 3.1.0
  • lib/timing.js ← nanotiming 7.3.1 (unified on global performance)
  • lib/dom.js ← document-ready 2.0.1 + scroll-to-anchor 1.0.0
  • lib/query.js — nanoquery replaced by URLSearchParams
• packages/html — @choojs/html: the rendering package.
  • server.js — server-side tagged template (← nanohtml 1.10.0 server, transform branches removed; pure runtime)
  • browser.js — runtime-only cached template tag: each template literal is parsed once (WeakMap keyed on its strings array) into a plus hole instructions; renders clone and fill. Values never pass through innerHTML. Document-level roots ( etc.) parse via DOMParser since drops them. Known limits: no dynamic tag names, no holes in raw-text elements, SVG fragments need their
  • morph.js — ← nanomorph 5.4.3, consolidated to one module
  • raw.js — mark pre-encoded strings (works with both renderers)
  • packages/component — @choojs/component: ← nanocomponent 6.6.0 + on-load 3.4.1 as ES classes; the future island/hydration boundary.
  • packages/devtools — @choojs/devtools: window.choo with live state, event log, timings via PerformanceObserver, copy(); no-op on the server.
  • packages/migrate — @choojs/migrate: the choo-migrate codemod. Regex-based on purpose: converts simple top-level CJS to ESM, remaps specifiers (choo → @choojs/core, nanohtml → @choojs/html, …), points retired packages at their replacements, and reports everything it refuses to guess at.
  • examples/counter — the isomorphic proof: one app module, mounted zero-build in the browser via import map (index.html), string-rendered in Node (render.js).
  • examples/streaming — streaming SSR demo server (node examples/streaming/server.js).

  Status vs the modernization plan

  • Phase 1: monorepo scaffold, ESM ports, choo v7 node test suite green on node --test (Node ≥ 24), CI on GitHub Actions
  • URL normalization fix: WHATWG URL parsing, single decode with raw fallback (no more URIError on '%'), NFC matching, per-segment wildcard decode, decoded state.href
  • Phase 2 (core): browser renderer rewrite, @choojs/component, zero-build counter example, full-app integration test in happy-dom
  • Phase 2 (tail): adoption-style hydration with mismatch warnings (@choojs/html/hydrate, wired into mount()), real-browser Playwright e2e (zero-build page, SSR-then-hydrate page, adoption proof; CI job included), benchmarks vs nanohtml v1 / µhtml

  Benchmarks (2026-09, 100-row table, npm run bench / bench:browser)

  Real Chromium: @choojs/html creates fresh trees ~12% faster than µhtml v5 (3.5k vs 3.1k ops/s) — the parse-once/clone design pays off in native DOM. µhtml updates in place ~5x faster than our fresh-tree + nanomorph loop (3.0k vs 0.6k ops/s): that is choo's architectural cost, mitigated in real apps by @choojs/component caching (proxy nodes skip unchanged subtrees), and the number to beat if Phase 3 explores keyed-hole optimizations. Server string rendering is on par with nanohtml v1 (~13k ops/s, within 6%). happy-dom numbers in bench/render.js are indicative only.

  • Phase 3: v8 wiring, all shipped together: - toStream(location, state) — web-standard ReadableStream of UTF-8; new Response(stream) on web servers, Readable.fromWeb(stream).pipe(res) on Node. Progressive: the server tag now builds a parts list, so promises/async iterables in child position flush the shell first and stream the rest in document order (proven byte-level and in real Chromium). - state.prefetch — stores push promises during init; toStream awaits them before rendering; toString refuses them loudly. - lazy(loader, loadingView?) — the answer to choojs/choo#653, both halves at once: browser renders the loading view (or holds the current tree) until the dynamic import lands, server awaits it in toStream; toString fails with guidance. Views cache after first load. - @choojs/devtools and the choo-migrate codemod (validated by migrating choo's own v7 example and running the result on v8).
  • Phase 3 follow-ups for the RFC: API shape feedback on lazy() (thenable handlers vs wrapper), serializing streamed state for hydration of async holes (bankai v10 territory).
  • Phase 4: bankai v10 (Vite 8/Rolldown shell, SSR middleware, 103 Early Hints, service worker, precompression)
  • Phase 5: docs, examples, launch

  Deliberate changes from v7

  • choo() still works without new; Choo is also a named export.
  • nanoquery → URLSearchParams (same output shape, repeated keys → arrays).
  • Assertions live in lib/assert.js so production builds can strip them.
  • Everything targets Node ≥ 24 and Baseline Widely Available browsers; there is no compile step and no transpilation anywhere.

  Attribution

  All ported modules are MIT-licensed work by the original choojs/nano* authors and contributors; per-file headers note the source package and version. This branch exists to carry that work forward, not to replace it.