A script to reproduce fetch's `getReader` streaming bug in bun.

bun-fetch-get-reader-streaming-bug.sh

#!/bin/bash

TIMESTAMP=$(date +%s)
mkdir "bun-fetch-get-reader-streaming-bug-$TIMESTAMP/"
cd "bun-fetch-get-reader-streaming-bug-$TIMESTAMP/"

cat <<EOT > package.json
{ "dependencies": { "express": "^4.18.2" }, "type": "module" }
EOT

cat <<EOT > index.js
import express from "express";
import { spawn } from "child_process";

const port = 3003;
const app = express();

async function sleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

app.get("/", async (req, res) => {
  res.set({ "transfer-encoding": "chunked" });
  res.write("1\n");
  await sleep(300);
  res.write("2\n");
  await sleep(300);
  res.write("3\n");
  await sleep(300);
  res.write("4\n");
  await sleep(300);
  res.write("5\n");
  await sleep(300);
  res.end();
});

app.listen(port, () => {
  console.log("Example app listening on port " + port);
  const child = spawn("node", ["fetch.js"]);
  child.stdout.on("data", (data) => {
    console.log("node: " + data);
  });
  child.stderr.on("data", (data) => {
    console.error("node: " + data);
  });
  child.on("close", (code) => {
    const child = spawn("bun", ["run", "fetch.js"]);
    child.stdout.on("data", (data) => {
      console.log("bun: " + data);
    });
    child.stderr.on("data", (data) => {
      console.error("bun: " + data);
    });
    child.on("close", (code) => {});
  });
});
EOT

cat <<EOT > fetch.js
async function fetchStreaming() {
  const res = await fetch("http://localhost:3003", {});
  if (!res.body) {
    console.log("No body")
    return
  }
  const reader = res.body.getReader();
  const decoder = new TextDecoder("utf-8");
  while (true) {
    const { done, value } = await reader.read();
    console.log("value", decoder.decode(value))
    if (done) {
      break;
    }
  }
}

fetchStreaming()
EOT

bun install
node index.js