bun.sh/test/js/node/http/node-fetch.test.js

import fetch2, { fetch, Response, Request, Headers } from "node-fetch";
import * as iso from "isomorphic-fetch";
import * as vercelFetch from "@vercel/fetch";
import * as stream from "stream";

import { test, expect } from "bun:test";

test("node-fetch", () => {
  expect(Response.prototype).toBeInstanceOf(globalThis.Response);
  expect(Request.prototype).toBeInstanceOf(globalThis.Request);
  expect(Headers.prototype).toBeInstanceOf(globalThis.Headers);
  expect(fetch2.default).toBe(fetch2);
  expect(fetch2.Response).toBe(Response);
});

test("node-fetch Headers.raw()", () => {
  const headers = new Headers({ "a": "1" });
  headers.append("Set-Cookie", "b=1");
  headers.append("Set-Cookie", "c=1");

  expect(headers.raw()).toEqual({
    "set-cookie": ["b=1", "c=1"],
    "a": ["1"],
  });
});

for (const [impl, name] of [
  [fetch, "node-fetch.fetch"],
  [fetch2, "node-fetch.default"],
  [fetch2.default, "node-fetch.default.default"],
  [iso.fetch, "isomorphic-fetch.fetch"],
  [iso.default.fetch, "isomorphic-fetch.default.fetch"],
  [iso.default, "isomorphic-fetch.default"],
  [vercelFetch.default(fetch), "@vercel/fetch.default"],
]) {
  test(name + " fetches", async () => {
    using server = Bun.serve({
      port: 0,
      fetch(req, server) {
        server.stop();
        return new Response("it works");
      },
    });
    expect(await impl("http://" + server.hostname + ":" + server.port)).toBeInstanceOf(globalThis.Response);
  });
}

test("node-fetch uses node streams instead of web streams", async () => {
  using server = Bun.serve({
    port: 0,
    async fetch(req, server) {
      const body = await req.text();
      expect(body).toBe("the input text");
      return new Response("hello world");
    },
  });

  {
    const result = await fetch2("http://" + server.hostname + ":" + server.port, {
      body: new stream.Readable({
        read() {
          this.push("the input text");
          this.push(null);
        },
      }),
      method: "POST",
    });
    expect(result.body).toBeInstanceOf(stream.Readable);
    expect(result.body === result.body).toBe(true); // cached lazy getter
    const headersJSON = result.headers.toJSON();
    for (const key of Object.keys(headersJSON)) {
      const value = headersJSON[key];
      headersJSON[key] = Array.isArray(value) ? value : [value];
    }
    expect(result.headers.raw()).toEqual(headersJSON);
    const chunks = [];
    for await (const chunk of result.body) {
      chunks.push(chunk);
    }
    expect(Buffer.concat(chunks).toString()).toBe("hello world");
  }
});