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node_modules/@sentry-internal/tracing/esm/browser/web-vitals/lib/getVisibilityWatcher.js

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+import { WINDOW } from '../../types.js';
+import { onHidden } from './onHidden.js';
+
+/*
+ * 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.
+ */
+
+let firstHiddenTime = -1;
+
+const initHiddenTime = () => {
+  // If the document is hidden and not prerendering, assume it was always
+  // hidden and the page was loaded in the background.
+  if (WINDOW.document && WINDOW.document.visibilityState) {
+    firstHiddenTime = WINDOW.document.visibilityState === 'hidden' && !WINDOW.document.prerendering ? 0 : Infinity;
+  }
+};
+
+const trackChanges = () => {
+  // Update the time if/when the document becomes hidden.
+  onHidden(({ timeStamp }) => {
+    firstHiddenTime = timeStamp;
+  }, true);
+};
+
+const getVisibilityWatcher = (
+
+) => {
+  if (firstHiddenTime < 0) {
+    // If the document is hidden when this code runs, assume it was hidden
+    // since navigation start. This isn't a perfect heuristic, but it's the
+    // best we can do until an API is available to support querying past
+    // visibilityState.
+    initHiddenTime();
+    trackChanges();
+  }
+  return {
+    get firstHiddenTime() {
+      return firstHiddenTime;
+    },
+  };
+};
+
+export { getVisibilityWatcher };
+//# sourceMappingURL=getVisibilityWatcher.js.map