1 files changed, 105 insertions, 0 deletions
diff --git a/frontend-old/node_modules/web-vitals/src/onFID.ts b/frontend-old/node_modules/web-vitals/src/onFID.ts
new file mode 100644
index 0000000..cde84b9
--- /dev/null
+++ b/frontend-old/node_modules/web-vitals/src/onFID.ts
@@ -0,0 +1,105 @@
+/*
+ * 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 {onBFCacheRestore} from './lib/bfcache.js';
+import {bindReporter} from './lib/bindReporter.js';
+import {getVisibilityWatcher} from './lib/getVisibilityWatcher.js';
+import {initMetric} from './lib/initMetric.js';
+import {observe} from './lib/observe.js';
+import {onHidden} from './lib/onHidden.js';
+import {
+  firstInputPolyfill,
+  resetFirstInputPolyfill,
+} from './lib/polyfills/firstInputPolyfill.js';
+import {runOnce} from './lib/runOnce.js';
+import {whenActivated} from './lib/whenActivated.js';
+import {
+  FIDMetric,
+  FirstInputPolyfillCallback,
+  MetricRatingThresholds,
+  ReportOpts,
+} from './types.js';
+
+/** Thresholds for FID. See https://web.dev/articles/fid#what_is_a_good_fid_score */
+export const FIDThresholds: MetricRatingThresholds = [100, 300];
+
+/**
+ * Calculates the [FID](https://web.dev/articles/fid) value for the current page and
+ * calls the `callback` function once the value is ready, along with the
+ * relevant `first-input` performance entry used to determine the value. The
+ * reported value is a `DOMHighResTimeStamp`.
+ *
+ * _**Important:** since FID is only reported after the user interacts with the
+ * page, it's possible that it will not be reported for some page loads._
+ */
+export const onFID = (
+  onReport: (metric: FIDMetric) => void,
+  opts?: ReportOpts,
+) => {
+  // Set defaults
+  opts = opts || {};
+
+  whenActivated(() => {
+    const visibilityWatcher = getVisibilityWatcher();
+    let metric = initMetric('FID');
+    let report: ReturnType<typeof bindReporter>;
+
+    const handleEntry = (entry: PerformanceEventTiming) => {
+      // Only report if the page wasn't hidden prior to the first input.
+      if (entry.startTime < visibilityWatcher.firstHiddenTime) {
+        metric.value = entry.processingStart - entry.startTime;
+        metric.entries.push(entry);
+        report(true);
+      }
+    };
+
+    const handleEntries = (entries: FIDMetric['entries']) => {
+      entries.forEach(handleEntry);
+    };
+
+    const po = observe('first-input', handleEntries);
+
+    report = bindReporter(
+      onReport,
+      metric,
+      FIDThresholds,
+      opts!.reportAllChanges,
+    );
+
+    if (po) {
+      onHidden(
+        runOnce(() => {
+          handleEntries(po.takeRecords() as FIDMetric['entries']);
+          po.disconnect();
+        }),
+      );
+
+      onBFCacheRestore(() => {
+        metric = initMetric('FID');
+        report = bindReporter(
+          onReport,
+          metric,
+          FIDThresholds,
+          opts!.reportAllChanges,
+        );
+
+        // Browsers don't re-emit FID on bfcache restore so fake it until you make it
+        resetFirstInputPolyfill();
+        firstInputPolyfill(handleEntry as FirstInputPolyfillCallback);
+      });
+    }
+  });
+};