The source code

    /**
     * @ignore
     * decorate its children from one element
     * @author yiminghe@gmail.com
     */
    KISSY.add("component/base/decorate-child", function (S, DecorateChildren) {
        function DecorateChild() {

        }

        S.augment(DecorateChild, DecorateChildren, {
            decorateInternal: function (element) {
                var self = this;
                // 不用 setInternal , 通知 view 更新
                self.set("el", element);
                var ui = self.get("decorateChildCls"),
                    prefixCls = self.get('prefixCls'),
                    child = element.one("." + ui);
                // 可以装饰?
                if (child) {
                    var UI = self.findUIConstructorByNode(prefixCls, child, 1);
                    if (UI) {
                        // 可以直接装饰
                        self.decorateChildrenInternal(UI, child);
                    } else {
                        // 装饰其子节点集合
                        self.decorateChildren(child);
                    }
                }
            }
        });

        return DecorateChild;
    }, {
        requires: ['./decorate-children']
    });