Function hierarchy

explainshell/web/static/js/d3.v3.js:5436–5440

(d)

      return v;
    }
    function hierarchy(d) {
      var nodes = [];
      recurse(d, 0, nodes);
      return nodes;
    }
    hierarchy.sort = function(x) {
      if (!arguments.length) return sort;
      sort = x;