var DBDeleteRequest = window.indexedDB.deleteDatabase("toDoList");

DBDeleteRequest.onerror = function(event) {
  console.log("Error deleting database.");
};
 
DBDeleteRequest.onsuccess = function(event) {
  console.log("Database deleted successfully");
    
  console.log(event.result); // should be undefined
};

// you must call db.close() before delete, if you already open. otherwise you will get onblocked event
DBDeleteRequest.onblocked = function () {
    console.log("Couldn't delete database due to the operation being blocked");
};

return window.indexedDB.databases()
    .then((dbs) => {
        dbs.map(db => {
            db.close();
            window.indexedDB.deleteDatabase(db.name)
        })
    }).catch(console.error);

/**
 * Checks IndexedDB for all IndexedDBs and deletes them if the username
 * is not the one provided. Used when changing users after session expires.
 *
 * @static
 * @param {String} usernameToKeep Current authenticated user
 * @returns
 * @memberof DB
 */
static purgeIndexedDB(usernameToKeep) {
  if (window.indexedDB && window.indexedDB.databases) {
    return window.indexedDB.databases()
      .then((dbs) => 
          dbs.filter((db) => (db.name.includes('_pouch_') && (!usernameToKeep || !db.name.includes(usernameToKeep)))))
      .then((IndexedDBS) => 
          Promise.all(IndexedDBS.map((IndexedDB) => window.indexedDB.deleteDatabase(IndexedDB.name))))
      .catch(console.error);
  }
  return false;
}