in src/converterHelper.ts [38:48]
export function categoryIsAlsoSeriesRole(dataView: DataViewCategorical, seriesRoleName: string, categoryRoleName: string): boolean {
if (dataView.categories && dataView.categories.length > 0) {
// Need to pivot data if our category soure is a series role
let category = dataView.categories[0];
return category.source &&
DataRoleHelper.hasRole(category.source, seriesRoleName) &&
DataRoleHelper.hasRole(category.source, categoryRoleName);
}
return false;
}