d3-dag/src/dag/depth.js

Layout algorithms for visualizing directed acylic graphs.

// Set each node's value to be zero for leaf nodes and the greatest distance to
// any leaf node for other nodes
export default function() {
  this.each((n) => {
    n.children.forEach((c) => (c._parents || (c._parents = [])).push(n));
  });
  this.eachBefore((n) => {
    n.value = Math.max(0, ...(n._parents || []).map((c) => 1 + c.value));
  });
  this.each((n) => delete n._parents);
  return this;
}