function getSortedData(data) {
            return d3Collection.nest()
                .key(getDate)
                .entries(
                    data.sort((a, b) => a.date - b.date)
                )
                .map(d => {
                    return assign({}, d, {
                        date: castValueToType(d.key, xAxisValueType)
                    });
                });
        }
Orders the data by date for consumption on the chart tooltip
@param  {areaChartData} data    Chart data
@return {Object[]}               Chart data ordered by date
@private