Update app and tooling

node_modules/web-vitals/dist/getTTFB.js

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { initMetric } from './lib/initMetric.js';
+const afterLoad = (callback) => {
+    if (document.readyState === 'complete') {
+        // Queue a task so the callback runs after `loadEventEnd`.
+        setTimeout(callback, 0);
+    }
+    else {
+        // Use `pageshow` so the callback runs after `loadEventEnd`.
+        addEventListener('pageshow', callback);
+    }
+};
+const getNavigationEntryFromPerformanceTiming = () => {
+    // Really annoying that TypeScript errors when using `PerformanceTiming`.
+    const timing = performance.timing;
+    const navigationEntry = {
+        entryType: 'navigation',
+        startTime: 0,
+    };
+    for (const key in timing) {
+        if (key !== 'navigationStart' && key !== 'toJSON') {
+            navigationEntry[key] = Math.max(timing[key] - timing.navigationStart, 0);
+        }
+    }
+    return navigationEntry;
+};
+export const getTTFB = (onReport) => {
+    const metric = initMetric('TTFB');
+    afterLoad(() => {
+        try {
+            // Use the NavigationTiming L2 entry if available.
+            const navigationEntry = performance.getEntriesByType('navigation')[0] ||
+                getNavigationEntryFromPerformanceTiming();
+            metric.value = metric.delta =
+                navigationEntry.responseStart;
+            metric.entries = [navigationEntry];
+            metric.isFinal = true;
+            onReport(metric);
+        }
+        catch (error) {
+            // Do nothing.
+        }
+    });
+};