In-memory IResponse double with snapshot() and ended getter.
Implements the full IResponse surface so that middleware tests can
inspect snapshot() (status, headers, body) and assert short-circuit
behavior via the ended getter. Chaining methods (status, header,
appendHeader) return this; terminal methods set #ended = true and
return a HandlerResult brand.
ended: boolean
appendHeader(name: string,value: string): IResponse
Appends a response header, preserving any existing values for the same
name rather than replacing them (unlike IResponse.header,
which overwrites). This is the correct way to emit multiple headers of the
same name — most notably several Set-Cookie headers (e.g. an access
cookie plus a refresh cookie, or deleting several cookies at once).
header(name: string,value: string): IResponse
Sets a response header.
html(_body: string): HandlerResult
Terminal HTML response — mirrors the kernel builder's html(), so a test
asserting on the double cannot pass where the real builder would fail.
json<T>(_body: T): HandlerResult
Sends a JSON response.
redirect(url: string,_status?: number): HandlerResult
Sends a redirect response.
send(_body?: Uint8Array): HandlerResult
Sends a raw byte response.
snapshot(): ResponseSnapshot
Returns a snapshot of the current response state (status, headers, body).
Enables middleware to inspect the response after next() returns —
required for transparent response caching.
The returned object is a READ view, not a defensive copy: headers is the
live Headers instance backing the response. Treat it as read-only —
mutating it mutates the response. (No copy is taken deliberately: cloning a
Headers collapses repeated Set-Cookie values into one comma-joined
header, which would corrupt multi-cookie responses.)
Returns a discriminated union keyed on streaming: when false,
body is Uint8Array | string | null (buffered); when true,
body is a ReadableStream<Uint8Array> (live stream). Middleware that
reads the body (e.g. cache middleware) must check streaming first to
avoid draining a live stream.
status(code: number): IResponse
Sets the response status code.
stream(body: ReadableStream<Uint8Array>): HandlerResult
Sends a streaming response body.
Accepts a web-standard ReadableStream so that a handler can flush
bytes progressively over a long-lived connection instead of buffering a
whole body before send. This is the shared foundation for Server-Sent Events
(Milestone 43), React SSR streaming (Milestone 44), large file downloads
(storage-plugin, Milestone 28), and export / report responses.
Because the runtime maps the response to a web-standard
new Response(streamBody, { status, headers }), streaming is free on every
platform (Node via Hono, Deno, Bun, Cloudflare Workers) with no buffer-then-send.
text(_body: string): HandlerResult
Sends a plain-text response.