in src/visual.ts [738:766]
private static getPercentChangeStartPoint(chartData: Array<IDualKpiDataPoint>, percentCalcDate: Date): IDualKpiDataPoint {
if (percentCalcDate !== null) {
let closestIndex = 0,
percentCalcDateTime = percentCalcDate.getTime(),
i, currTime;
// keep track of closest date to configured date
// as soon as we find a date that is more recent than configured date
// break and use the last date that was older than configured date.
// always break if we find a date that is exactly equal
for (i = 0; i < chartData.length; i++) {
currTime = chartData[i].date.getTime();
if (currTime === percentCalcDateTime) {
closestIndex = i;
break;
}
else if (currTime < percentCalcDateTime) {
closestIndex = i;
}
else {
break;
}
}
return chartData[closestIndex];
}
return chartData[0];
}