Res Stream

Stage 2: an incremental `res` Writable. The handler calls res.write several times mid-execution — each chunk is framed straight to the socket with chunked transfer-encoding, rather than buffered until the handler returns — then res.end closes the response. The server fetches its own endpoint and consumes the chunks incrementally through fetch's streaming Response.body, proving the response streams rather than arriving whole.

import http from 'http';
import type { AddressInfo } from 'net';

async function consume(port: number): Promise<void> {
  const res = await fetch("http://127.0.0.1:" + port + "/");
  const decoder = new TextDecoder();
  let text = "";
  for await (const piece of res.body!) {
    text = text + decoder.decode(piece);
  }
  console.log("streamed:", text);
  process.exit(0);
}

const server = http.createServer((req: http.IncomingMessage, res: http.ServerResponse) => {
  res.writeHead(200, { "Content-Type": "text/plain" });
  res.write("alpha ");
  res.write("beta ");
  res.write("gamma");
  res.end();
});

server.listen(0, () => {
  const port: number = (server.address() as AddressInfo).port;
  console.log("listening:", port > 0);
  setTimeout(() => { consume(port); }, 50);
});

View source on GitHubexamples/http/res_stream.ts

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