src/services/bfcache.ts

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *      http://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 function onBFCacheRestore(cb: onBFCacheRestoreCallback) {
  addEventListener(
    'pageshow',
    (event) => {
      if (event.persisted) {
        bfcacheRestoreTime = event.timeStamp;
        cb(event);
      }
    },
    true,
  );
};