in src/radarChart.ts [262:271]
public static checkAndUpdateAxis(dataView: DataView, values: DataViewValueColumns) {
if (dataView.categorical.categories[0].values.length <= 2) {// add 2-3 categories to make it looks like a rhomb
for (let i: number = dataView.categorical.categories[0].values.length; i < RadarChart.minimumAxisCount; i++) {
dataView.categorical.categories[0].values.push(" ");
for (let j: number = 0; j < values.length; j++) {
values[j].values.push(RadarChart.fakeValue);
}
}
}
}