insertElement (elem, text) {
    if (!this.undoManager_) { return this }
    this.addCommand_(new InsertElementCommand(elem, text))
    return this
  }
Add an `InsertElementCommand` to the history or current batch command.
@param {Element} elem - The DOM element that was added
@param {string} [text] - An optional string visible to user related to this change
@returns {module:history.HistoryRecordingService}