chromium/third_party/blink/web_tests/external/wpt/service-workers/service-worker/resources/type-check-worker.js

let type = '';
try {
  importScripts('empty.js');
  type = 'classic';
} catch (e) {
  type = 'module';
}
onmessage = e => {
  e.source.postMessage(type);
};