code: function createTooltipItem(element) {
  	var xScale = element._xScale;
  	var yScale = element._yScale || element._scale; // handle radar || polarArea charts
  	var index = element._index;
  	var datasetIndex = element._datasetIndex;
  	var controller = element._chart.getDatasetMeta(datasetIndex).controller;
  	var indexScale = controller._getIndexScale();
  	var valueScale = controller._getValueScale();
  
  	return {
  		xLabel: xScale ? xScale.getLabelForIndex(index, datasetIndex) : '',
  		yLabel: yScale ? yScale.getLabelForIndex(index, datasetIndex) : '',
  		label: indexScale ? '' + indexScale.getLabelForIndex(index, datasetIndex) : '',
  		value: valueScale ? '' + valueScale.getLabelForIndex(index, datasetIndex) : '',
  		index: index,
  		datasetIndex: datasetIndex,
  		x: element._model.x,
  		y: element._model.y
  	};
  }
docs: Private helper to create a tooltip item model
  @param element - the chart element (point, arc, bar) to create the tooltip item for
  @return new tooltip item