dist/d3-sankey-circular.es.js
function center(node) {
  return node.targetLinks.length ? node.depth : node.sourceLinks.length ? min(node.sourceLinks, targetDepth) - 1 : 0;
}
function center(node) {
  return node.targetLinks.length ? node.depth : node.sourceLinks.length ? min(node.sourceLinks, targetDepth) - 1 : 0;
}
The depth of a node when the nodeAlign (align) is set to 'center'