vue使用indexDB判断数据库是否存在判断表是否存在

let dbName = 'hist-data-1d'
      const dbs = await window.indexedDB.databases(dbName);
      const dbExists = dbs.some((db) => db.name === dbName);

      if (!dbExists) {
        const openReq = indexedDB.open(dbName, 1);
        openReq.onerror = (event) => {
          console.log('dbExists,创建数据库失败', dbExists)
        };
      } else {
        const request = indexedDB.open(dbName);
        request.onerror = (event) => {
          console.log('数据库连接打开失败', event);
        };

   request.onsuccess = async (event) => {
            let db = event.target.result;
            let tablesObj = db.objectStoreNames;
            const version = db.version;

            if (tablesObj.contains(tableName)) {
              console.log(`存在名为 ${tableName} 的对象存储。`);
             
            } else { }

          }