refactor sidebar && add nested demo

src/router/index.js

@@ -72,6 +72,64 @@ export const constantRouterMap = [
     ]
   },
 
+  {
+    path: '/nested',
+    component: Layout,
+    redirect: '/nested/menu1',
+    name: 'nested',
+    meta: {
+      title: 'nested',
+      icon: 'nested'
+    },
+    children: [
+      {
+        path: 'menu1',
+        component: () => import('@/views/nested/menu1/index'), // Parent router-view
+        name: 'menu1',
+        meta: { title: 'menu1' },
+        children: [
+          {
+            path: 'menu1-1',
+            component: () => import('@/views/nested/menu1/menu1-1'),
+            name: 'menu1-1',
+            meta: { title: 'menu1-1' }
+          },
+          {
+            path: 'menu1-2',
+            component: () => import('@/views/nested/menu1/menu1-2'),
+            name: 'menu1-2',
+            meta: { title: 'menu1-2' },
+            children: [
+              {
+                path: 'menu1-2-1',
+                component: () => import('@/views/nested/menu1/menu1-2/menu1-2-1'),
+                name: 'menu1-2-1',
+                meta: { title: 'menu1-2-1' }
+              },
+              {
+                path: 'menu1-2-2',
+                component: () => import('@/views/nested/menu1/menu1-2/menu1-2-2'),
+                name: 'menu1-2-2',
+                meta: { title: 'menu1-2-2' }
+              }
+            ]
+          },
+          {
+            path: 'menu1-3',
+            component: () => import('@/views/nested/menu1/menu1-3'),
+            name: 'menu1-3',
+            meta: { title: 'menu1-3' }
+          }
+        ]
+      },
+      {
+        path: 'menu2',
+        component: () => import('@/views/nested/menu2/index'),
+        meta: { title: 'menu2' }
+      }
+    ]
+  },
+
   { path: '*', redirect: '/404', hidden: true }
 ]