function createTooltipItem(chart, item) {
  const {element, datasetIndex, index} = item;
  const controller = chart.getDatasetMeta(datasetIndex).controller;
  const {label, value} = controller.getLabelAndValue(index);

  return {
    chart,
    label,
    parsed: controller.getParsed(index),
    raw: chart.data.datasets[datasetIndex].data[index],
    formattedValue: value,
    dataset: controller.getDataset(),
    dataIndex: index,
    datasetIndex,
    element
  };
}
Private helper to create a tooltip item model
@param {Chart} chart
@param {ActiveElement} item - {element, index, datasetIndex} to create the tooltip item for
@return new tooltip item