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// This worker attempts to call respondWith() asynchronously after the
// fetch event handler finished. It reports back to the test whether
// an exception was thrown.
// These get reset at the start of a test case.
let reportResult;
// The test page sends a message to tell us that a new test case is starting.
// We expect a fetch event after this.
self.addEventListener('message', (event) => {
// Ensure tests run mutually exclusive.
if (reportResult) {
event.source.postMessage('testAlreadyRunning');
return;
}
const resultPromise = new Promise((resolve) => {
reportResult = resolve;
// Tell the client that everything is initialized and that it's safe to
// proceed with the test without relying on the order of events (which some
// browsers like Chrome may not guarantee).
event.source.postMessage('messageHandlerInitialized');
});
// Keep the worker alive until the test case finishes, and report
// back the result to the test page.
event.waitUntil(resultPromise.then(result => {
reportResult = null;
event.source.postMessage(result);
}));
});
// Calls respondWith() and reports back whether an exception occurred.
function tryRespondWith(event) {
try {
event.respondWith(new Response());
reportResult({didThrow: false});
} catch (error) {
reportResult({didThrow: true, error: error.name});
}
}
function respondWithInTask(event) {
setTimeout(() => {
tryRespondWith(event);
}, 0);
}
function respondWithInMicrotask(event) {
Promise.resolve().then(() => {
tryRespondWith(event);
});
}
self.addEventListener('fetch', function(event) {
const path = new URL(event.request.url).pathname;
const test = path.substring(path.lastIndexOf('/') + 1);
// If this is a test case, try respondWith() and report back to the test page
// the result.
if (test == 'respondWith-in-task') {
respondWithInTask(event);
} else if (test == 'respondWith-in-microtask') {
respondWithInMicrotask(event);
}
});