index.js

/*
 * Copyright 2019 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 unsupported;

const useSaveData = (initialSaveData = null) => {
  if (typeof navigator !== 'undefined' && 'connection' in navigator && 'saveData' in navigator.connection) {
    unsupported = false;
  } else {
    unsupported = true;
  }

  return {
    unsupported,
    saveData: unsupported
      ? initialSaveData
      : navigator.connection.saveData === true
  };
};

export { useSaveData };