refs #441 Add scroll top button in tag

src/renderer/components/TimelineSpace/Contents/Hashtag/Tag.vue

@@ -9,12 +9,17 @@
     </div>
   </transition-group>
   <div class="loading-card" v-loading="lazyLoading" :element-loading-background="backgroundColor"></div>
+  <div class="upper" v-show="!heading">
+    <el-button type="primary" icon="el-icon-arrow-up" @click="upper" circle>
+    </el-button>
+  </div>
 </div>
 </template>
 
 <script>
 import { mapState } from 'vuex'
 import Toot from '../Cards/Toot'
+import scrollTop from '../../../utils/scroll'
 
 export default {
   name: 'tag',
@@ -151,6 +156,12 @@ export default {
       } finally {
         this.$store.commit('TimelineSpace/changeLoading', false)
       }
+    },
+    upper () {
+      scrollTop(
+        document.getElementById('scrollable'),
+        0
+      )
     }
   }
 }
@@ -178,5 +189,11 @@ export default {
 .loading-card:empty {
   height: 0;
 }
+
+.upper {
+  position: fixed;
+  bottom: 20px;
+  right: 20px;
+}
 </style>
 <style src="@/assets/timeline-transition.scss"></style>