whole_func_string: function treeMap(node, mapfn) {
    var results = [];
    nodeWalk(node, function(node) {
      results = results.concat(mapfn(node));
      return false;
    });
    return results;
  }
func_code_string: function treeMap(node, mapfn) {
    var results = [];
    nodeWalk(node, function(node) {
      results = results.concat(mapfn(node));
      return false;
    });
    return results;
  }
func_documentation_string: Applies `mapfn` to `node` and the tree below `node`, returning a flattened
  list of results.