d3/src/core/transition-select.js

A small, free JavaScript library for manipulating documents based on data.

d3_transitionPrototype.select = function(selector) {
  var subgroups = [],
      subgroup,
      subnode,
      node;

  if (typeof selector !== "function") selector = d3_selection_selector(selector);

  for (var j = -1, m = this.length; ++j < m;) {
    subgroups.push(subgroup = []);
    for (var group = this[j], i = -1, n = group.length; ++i < n;) {
      if ((node = group[i]) && (subnode = selector.call(node.node, node.node.__data__, i))) {
        if ("__data__" in node.node) subnode.__data__ = node.node.__data__;
        subgroup.push({node: subnode, delay: node.delay, duration: node.duration});
      } else {
        subgroup.push(null);
      }
    }
  }

  return d3_transition(subgroups, this.id).ease(this.ease());
};