code: function (name) {
          var children = this._children;
          for (var i = 0; i < children.length; i++) {
              var child = children[i];
              if (child.name === name) {
                  return child;
              } else {
                  var res = child.getDescendantByName(name);
                  if (res) {
                      return res;
                  }
              }
          }
      }
docs: Get first descendant have the given name
  @param {string} name
  @return {clay.Node}