@youneed/server-adapter

Run one @youneed/server app on any runtime — Node, Bun, Deno, or an edge / serverless fetch handler (Cloudflare Workers, Vercel/Netlify edge, Lambda function URLs).

The server core speaks node:http (req, res). This package bridges it to the Web fetch(Request) => Response shape every other runtime exposes.

import { Application } from "@youneed/server";
import { serve, toFetchHandler } from "@youneed/server-adapter";

const app = Application().get("/hello", () => ({ hello: "world" }));

// 1) One-liner that works on Node / Bun / Deno (auto-detects the runtime):
const server = await serve(app, { port: 3000 });
console.log(server.runtime, server.url); // "node http://localhost:3000"

// 2) A raw Web fetch handler for edge / serverless:
export default { fetch: toFetchHandler(app) };          // Cloudflare Worker
// Bun:  Bun.serve({ fetch: toFetchHandler(app) })
// Deno: Deno.serve(toFetchHandler(app))

How it works

app.handler() (added to @youneed/server) returns a runtime-agnostic Node request listener over the compiled routes. toFetchHandler(app) builds it once, then per request:

• shims the incoming Request into a Node IncomingMessage (method, url, headers, buffered body);
• collects the Node ServerResponse into a streaming Response (status + headers committed on the first write, body piped through a ReadableStream, so SSE / file streaming keep working);
• no-body statuses (204/205/304/101) resolve to a Response with a null body.

Adapters

nodeAdapter, bunAdapter, denoAdapter each implement RuntimeAdapter (available() + serve()). detectAdapter() returns the one matching the current runtime (Bun → Deno → Node). serve(app, opts) uses it.

app.handler() is a stateless dispatcher: plugin onListen/shutdown lifecycle runs only via app.listen(). For lifecycle-heavy apps on Node, prefer app.listen(); the fetch bridge is for runtimes that have no node:http.