如何动态增减左侧菜单？

采用如下方法动态添加菜单，可以显示，但是标签选项卡出不来，控制台报错
methods: {
loadMenu() {
for(var idx in this.$router.options.routes){
console.log(this.$router.options.routes[idx]);
}
this.$router.options.routes[7].children.push( {
path: 'hello_add',
icon: 'compose',
name: 'hello_add',
title: '动态添加Hello测试',
component: resolve => { require(['@/yttest/modules/simpletest/hello/hello_add.vue'], resolve); }
});
this.$router.addRoutes(this.$router.options.routes);
this.$store.commit('updateMenulist');
}
},

Start with the loadMenu method shown in the issue, especially the route mutation, addRoutes call, and updateMenulist commit. Reproduce the console error and trace the existing router, menu, and tab handling; done means a dynamically added route displays its corresponding menu entry and tab without errors.

Written by the indexing model from the issue text.