LayoutTests/http/tests/workers/service/resources/ServiceWorkerGlobalScope-properties-worker.js - WebKit - Git at Google

 self.addEventListener("message", (event) => {
     let result = eval(event.data);
     event.source.postMessage(event.data + " returned " + JSON.stringify(result));
 });
	self.addEventListener("message", (event) => {
	let result = eval(event.data);
	event.source.postMessage(event.data + " returned " + JSON.stringify(result));
	});