dist/d3-sankey-circular.es.js
function selfLinking(link, id) {
  return getNodeID(link.source, id) == getNodeID(link.target, id);
}
function selfLinking(link, id) {
  return getNodeID(link.source, id) == getNodeID(link.target, id);
}
check if link is self linking, ie links a node to the same node