Coding agents

Coding agents

Read this before writing or changing chttp code. The core is authored in the scriptc compilable subset, so some normal TypeScript is banned.

Give an agent the docs

These docs are published for agents too: llms.txt is the page index, llms-full.txt is every page in one file. Point your agent at either.

Subset rules for packages/router/src

  • | null unions only. Never undefined.
  • No Object.create(null), Object.freeze. Plain ({}) records only.
  • Classes only for the router’s entity types (CtxCore/Ctx, ReqViewCore/ReqView, the response sinks, HttpError).
  • Indexed for loops or for...of over arrays. Never for...in.
  • No new Function, eval, non-program instanceof, object or method shorthand.
  • Concrete types on route and middleware tables. No any[] or unknown[].
  • Never detect promises with typeof r.then or instanceof Promise. Dispatch settles non-settled results by await inside settleChain.
// ok
for (let i = 0; i < routes.length; i++) {}
const rec: { [k: string]: string } = {};

// banned
for (const k in rec) {}
const fns = { run: function (): void {} };

Shape of the code

  • One core file, packages/router/src/index.ts: router, context, dispatch, the Node-shaped app.handler() adapter, and the Web Standards-shaped app.fetch().
  • A second core file, packages/router/src/sink.ts: the ResponseSink abstraction plus NodeResponseSink (writes to ServerResponse) and FetchResponseSink (captures into a Web Response). Ctx holds a ResponseSink; both surfaces route through the same chain.
  • Route data is plain records. Handlers live in App._fns, nodes carry indices.
  • Matching uses an explicit frame stack, no recursion.
  • Response helpers call the sink at statement level. app.fetch() finalizes the sink to a Response in the chained promise; app.handler() finalizes by writing to res.end().

Where to read more

Previous Middleware