refactor: add keep-alive

src/views/example/table/index.vue

 <template>
-  <router-view></router-view>
+  <keep-alive>
+    <router-view></router-view>
+  </keep-alive>
 </template>

src/views/layout/components/AppMain.vue

 <template>
-	<section class="app-main" style="min-height: 100%">
-		<transition name="fade" mode="out-in">
-			<router-view :key="key"></router-view>
-		</transition>
-	</section>
+  <section class="app-main" style="min-height: 100%">
+    <transition name="fade" mode="out-in">
+      <keep-alive>
+        <router-view></router-view>
+      </keep-alive>
+    </transition>
+  </section>
 </template>
 
 <script>
 export default {
-  name: 'AppMain',
-  computed: {
-    key() {
-      return this.$route.name !== undefined ? this.$route.name + +new Date() : this.$route + +new Date()
-    }
-  }
+  name: 'AppMain'
 }
 </script>