code: function (callbackId) {
      const sender = this.sender
      if (!supportLocalStorage) {
        return callNotSupportFail(sender, callbackId)
      }
      try {
        const _arr = []
        for (let i = 0; i < localStorage.length; i++) {
          _arr.push(localStorage.key(i))
        }
        sender.performCallback(callbackId, {
          result: SUCCESS,
          data: _arr
        })
      }
      catch (e) {
        // accept any exception thrown during a storage attempt as a quota error
        callFail(sender, callbackId)
      }
    }
docs: Returns an array that contains all keys stored in Storage object.
  @param {function} callbackId