Vue+Element-ui实现左侧二级导航（可配置路由、所有路由层级可统一、可根据路由高亮菜单项、刷新时可自动展开定位到当前路由）

这里使用的Element文档版本是2.13.1。

路由文件index.js：

import Vue from 'vue'
import Router from 'vue-router'
import Login from '@/components/Login'
import Main from '@/components/Main'
import Form from '@/components/Form'
import Data from '@/components/Data'
import Radio from '@/components/Radio'
import Checkbox from '@/components/Checkbox'
import Table from '@/components/Table'
import Tag from '@/components/Tag'
import Button from '@/components/Button'
import Tabs from '@/components/Tabs'
import Echarts from '@/components/Echarts'
import Dialog from '@/components/Dialog'
import Tree from '@/components/Tree'

Vue.use(Router);

let router = new Router({
  mode: 'hash',
  routes: [
    {
      path: '/',
      name: 'index',
      redirect: '/login'
    },
    {
      path: '/login',
      name: 'login',
      component: Login,
      meta: {
        title: 'Login'
      }
    },
    {
      path: '/main',
      alias: '/main',
      name: 'main',
      component: Main,
      meta: {
        title: 'Main'
      },
      children: [
        {
          path: '/main/form',
          alias: '/form',
          name: 'form',
          component: Form,
          meta: {
            title: 'Form',
            icon: 'el-icon-eleme',
            requireAuth: true
          },
          children: [
            {
              path: '/main/form/radio',
              alias: '/radio',
              name: 'radio',
              component: Radio,
              meta: {
                title: 'Radio',
                requireAuth: true
              }
            },
            {
              path: '/main/form/checkbox',
              alias: '/checkbox',
              name: 'checkbox',
              component: Checkbox,
              meta: {
                title: 'Checkbox',
                requireAuth: true
              }
            }
          ]
        },
        {
          path: '/main/data',
          alias: '/data',
          name: 'data',
          component: Data,
          meta: {
            title: 'Data',
            icon: 'el-icon-upload',
            requireAuth: true
          },
          children: [
            {
              path: '/main/data/table',
              alias: '/table',
              name: 'table',
              component: Table,
              meta: {
                title: 'Table',
                requireAuth: true
              }
            },
            {
              path: '/main/data/tag',
              alias: '/tag',
              name: 'tag',
              component: Tag,
              meta: {
                title: 'Tag',
                requireAuth: true
              }
            }
          ]
        },
        {
          path: '/main/button',
          alias: '/button',
          name: 'button',
          component: Button,
          meta: {
            title: 'Button',
            icon: 'el-icon-s-order',
            requireAuth: true
          }
        },
        {
          path: '/main/tabs',
          alias: '/tabs',
          name: 'tabs',
          component: Tabs,
          meta: {
            title: 'Tabs',
            icon: 'el-icon-s-flag',
            requireAuth: true
          }
        },
        {
          path: '/main/echarts',
          alias: '/echarts',
          name: 'echarts',
          component: Echarts,
          meta: {
            title: 'Echarts',
            icon: 'el-icon-s-data',
            requireAuth: true
          }
        },
        {
          path: '/main/dialog',
          alias: '/dialog',
          name: 'dialog',
          component: Dialog,
          meta: {
            title: 'Dialog',
            icon: 'el-icon-phone',
            requireAuth: true
          }
        }
      ]
    },
    {
      path: '/tree',
      alias: '/tree',
      name: 'tree',
      component: Tree,
      meta: {
        title: 'Tree',
        icon: 'el-icon-s-marketing',
        requireAuth: true
      }
    }
  ]
});

export default router

router.beforeEach((to, from, next) => {
  let islogin = localStorage.getItem("islogin");
  islogin = Boolean(Number(islogin));
 
  if(to.path == "/login"){
    if(islogin){
      next("/main/form/radio");
    }else{
      next();
    }
  }else{
    // requireAuth:可以在路由元信息指定哪些页面需要登录权限
    if(to.meta.requireAuth && islogin) {
      next();
    }else{
      next("/login");
    }
  }
})

关键：除了login之外，其它都加上alias属性。

Main.vue：

<template>
  <div id="app">
    <el-container style="height: 100%;">
      <el-header style="height: 80px;" :style="topBg">
        <Header />
      </el-header>
      <el-container>
        <el-aside width="210px" :style="leftBg">
          <el-row class="tac">
            <el-col :span="24">
              <el-menu
                :default-active="$route.path"
                class="el-menu-vertical-demo"
                @open="handleOpen"
                @close="handleClose"
                background-color="none"
                text-color="#fff"
                active-text-color="#ff0000"
              >
                <template v-for="route in this.$router.options.routes[2].children">
                  <!-- 循环有子目录的菜单 -->
                  <el-submenu
                    :key="route.alias"
                    :index="route.alias"
                    v-if="route.children && route.children.length"
                  >
                    <template slot="title">
                      <i :class="route.meta.icon"></i>
                      <span>{{route.meta.title}}</span>
                    </template>
                    <el-menu-item-group>
                      <router-link
                        :to="subroute.alias"
                        :key="subroute.alias"
                        v-for="subroute in route.children"
                      >
                        <el-menu-item :index="subroute.alias">{{subroute.meta.title}}</el-menu-item>
                      </router-link>
                    </el-menu-item-group>
                  </el-submenu>
                  <!-- 循环有子目录的菜单 -->

                  <!-- 循环没有子目录的菜单 -->
                  <router-link
                    :to="route.alias"
                    :key="route.alias"
                    v-else-if="!route.children && route.alias != '/' && route.alias != '/login'"
                  >
                    <el-menu-item :index="route.alias">
                      <i :class="route.meta.icon"></i>
                      <span slot="title">{{route.meta.title}}</span>
                    </el-menu-item>
                  </router-link>
                  <!-- 循环没有子目录的菜单 -->
                </template>
              </el-menu>
            </el-col>
          </el-row>
        </el-aside>
        <el-main>
          <router-view></router-view>
        </el-main>
      </el-container>
    </el-container>
  </div>
</template>
 
<script>
import Header from "@/components/Header";
export default {
  name: "App",
  data() {
    return {
      leftBg: {
        background:
          "#235d8b url(" +
          require("../assets/left-bg.png") +
          ") no-repeat scroll 0 bottom"
      },
      topBg: {
        background:
          "#235d8b url(" +
          require("../assets/top-bg.png") +
          ") no-repeat scroll right 0",
        height: "80px",
        fontSize: "32px",
        color: "#ffffff"
      }
    };
  },
  components: {
    Header
  },
  methods: {
    handleOpen(key, keyPath) {
      console.log(key, keyPath);
    },
    handleClose(key, keyPath) {
      console.log(key, keyPath);
    }
  }
};
</script>
 
<style>
#app {
  font-family: "Avenir", Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  color: #2c3e50;
  height: 100%;
}

.el-header,
.el-footer {
  background-color: #b3c0d1;
  color: #333;
  line-height: 80px;
}

.el-aside {
  background-color: #d3dce6;
  color: #333;
}

.el-aside a {
  text-decoration: none;
}

.el-menu {
  background: none;
  border-right: 0;
}

.el-submenu__title{
  background: none!important;
}

.el-menu-item-group .el-menu-item {
  padding-left: 52px !important;
}
.el-menu-item{
  background: none!important;
}
.el-menu-item.is-active {
  color: #409eff;
  background: #ffffff!important;
}

.el-main {
  background-color: #ffffff;
  color: #333;
  padding: 0;
}

body > .el-container {
  margin-bottom: 40px;
}

.el-container:nth-child(5) .el-aside,
.el-container:nth-child(6) .el-aside {
  line-height: 260px;
}

.el-container:nth-child(7) .el-aside {
  line-height: 320px;
}
</style>

其中关键是：

根据路由高亮list、刷新自动展开定位路由由这个来控制：

:default-active="$route.path"

循环路由：

<template v-for="route in this.$router.options.routes[2].children">......</template>

另一个关键：

'<el-menu>'中的'<router-link></router-link>'，不然没法导航到相关组件。

Form.vue、Data.vue组件模板中需要添加'<router-view></router-view>'。