chromium/src/third_party/blink/web_tests/http/tests/devtools/service-workers/resources/v8-cache-worker.js

const cacheName = 'c8-cache-test';
const scriptName = '/devtools/resources/v8-cache-script.js';

self.addEventListener('install', (event) => {
    event.waitUntil(
      caches.open(cacheName)
        .then((cache) => cache.add(new Request(scriptName))));
  });

self.addEventListener('fetch', (event) => {
    if (event.request.url.indexOf(scriptName) == -1) {
      return;
    }
    event.respondWith(
      caches.open(cacheName)
        .then((cache) => {
          return cache.match(new Request(scriptName));
        })
    );
  });