startBatchCommand (text) {
    if (!this.undoManager_) { return this }
    this.currentBatchCommand_ = new BatchCommand(text)
    this.batchCommandStack_.push(this.currentBatchCommand_)
    return this
  }
Start a batch command so multiple commands can recorded as a single history command.
Requires a corresponding call to endBatchCommand. Start and end commands can be nested.

@param {string} text - Optional string describing the batch command.
@returns {module:history.HistoryRecordingService}