code: function diffDataProps(props, oldProps) {
    if (oldProps === null) {
      return 'oldProps is null, initial diff';
    }
  
    // Support optional app defined comparison of data
    const {dataComparator} = props;
    if (dataComparator) {
      if (!dataComparator(props.data, oldProps.data)) {
        return 'Data comparator detected a change';
      }
      // Otherwise, do a shallow equal on props
    } else if (props.data !== oldProps.data) {
      return 'A new data container was supplied';
    }
  
    return null;
  }
docs: The comparison of the data prop requires special handling the dataComparator should be used if supplied