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Stream Response

Fetch API Response objects made from async generators. Build streaming HTML responses or SSE with JS sugar.


async function* generate() {
  for await (const row of iterAllRows()) {
    yield `${row.join(',')}\n`

router.get('/large.csv', () => new StreamResponse(generate(), { 
  headers: [['content-type', 'text/csv']] 

Creating a SSE endpoint works much the same way:

async function* sse() {
  while (true) {
    await new Promise(r => setTimeout(r, 1000));
    yield 'data: hello\n\n';

router.get('/sse', contentType(['text/event-stream']), (req, { type }) => {
  return new StreamResponse(sse(), { headers: [['content-type', type]] })

*[SSE]: Server Sent Events

This module is part of the Worker Tools collection

Worker Tools are a collection of TypeScript libraries for writing web servers in Worker Runtimes such as Cloudflare Workers, Deno Deploy and Service Workers in the browser.

If you liked this module, you might also like:

  • 🧭 Worker Router — Complete routing solution that works across CF Workers, Deno and Service Workers
  • 🔋 Worker Middleware — A suite of standalone HTTP server-side middleware with TypeScript support
  • 📄 Worker HTML — HTML templating and streaming response library
  • 📦 Storage Area — Key-value store abstraction across Cloudflare KV, Deno and browsers.
  • 🆗 Response Creators — Factory functions for responses with pre-filled status and status text
  • 🎏 Stream Response — Use async generators to build streaming responses for SSE, etc…
  • 🥏 JSON Fetch — Drop-in replacements for Fetch API classes with first class support for JSON.
  • 🦑 JSON Stream — Streaming JSON parser/stingifier with first class support for web streams.

Worker Tools also includes a number of polyfills that help bridge the gap between Worker Runtimes:

Fore more visit