1 files changed, 36 insertions, 0 deletions
diff --git a/frontend-old/node_modules/web-vitals/src/lib/bfcache.ts b/frontend-old/node_modules/web-vitals/src/lib/bfcache.ts
new file mode 100644
index 0000000..647b731
--- /dev/null
+++ b/frontend-old/node_modules/web-vitals/src/lib/bfcache.ts
@@ -0,0 +1,36 @@
+/*
+ * 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.
+ */
+
+interface onBFCacheRestoreCallback {
+  (event: PageTransitionEvent): void;
+}
+
+let bfcacheRestoreTime = -1;
+
+export const getBFCacheRestoreTime = () => bfcacheRestoreTime;
+
+export const onBFCacheRestore = (cb: onBFCacheRestoreCallback) => {
+  addEventListener(
+    'pageshow',
+    (event) => {
+      if (event.persisted) {
+        bfcacheRestoreTime = event.timeStamp;
+        cb(event);
+      }
+    },
+    true,
+  );
+};