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HTTP2 server push

Push static assets to a client's browser without waiting for HTML to render.

const CSS = `body { color: red; }`;
const HTML = `
<!doctype html>
<html lang="en">
<meta charset="utf-8">
<title>Server push test</title>
<link rel="stylesheet" href="http2_push/h2p/test.css">
<h1>Server push test page</h1>
export default {
fetch(req) {
// If request is for test.css, serve the raw CSS
if (/test\.css$/.test(req.url)) {
return new Response(CSS, {
headers: {
"content-type": "text/css",
// Serve raw HTML using HTTP/2 for the CSS file
return new Response(HTML, {
headers: {
"content-type": "text/html",
Link: "</http2_push/h2p/test.css>; rel=preload; as=style",