function getMinValueByDate() {
            let keys = uniq(data.map(o => o.name));
            let minValueByDate = d3Array.min(dataSortedFormatted, function(d){
                let vals = keys.map((key) => d[key]);

                return d3Array.sum(vals);
            });

            return minValueByDate;
        }
Computes the minimal sum of values for any date

@return {Number} Min value