refs #1766 Introduce vue-virtual-scroll in Notifications

src/renderer/components/TimelineSpace/Contents/Notifications.vue

@@ -2,22 +2,24 @@
   <div id="notifications" v-shortkey="shortcutEnabled ? { next: ['j'] } : {}" @shortkey="handleKey">
     <div class="unread">{{ unread.length > 0 ? unread.length : '' }}</div>
     <div v-shortkey="{ linux: ['ctrl', 'r'], mac: ['meta', 'r'] }" @shortkey="reload()"></div>
-    <transition-group name="timeline" tag="div">
-      <div class="notifications" v-for="message in notifications" v-bind:key="message.id">
+    <DynamicScroller :items="notifications" :min-item-size="20" class="scroller" page-mode>
+      <template v-slot="{ item, index, active }">
+        <DynamicScrollerItem :item="item" :active="active" :size-dependencies="[item.url]" :data-index="index">
           <notification
-          :message="message"
+            :message="item"
             :filter="filter"
-          :focused="message.id === focusedId"
+            :focused="item.id === focusedId"
             :overlaid="modalOpened"
             v-on:update="updateToot"
             @focusNext="focusNext"
             @focusPrev="focusPrev"
             @focusRight="focusSidebar"
-          @selectNotification="focusNotification(message)"
+            @selectNotification="focusNotification(item)"
           >
           </notification>
-      </div>
-    </transition-group>
+        </DynamicScrollerItem>
+      </template>
+    </DynamicScroller>
     <div class="loading-card" v-loading="lazyLoading" :element-loading-background="backgroundColor"></div>
     <div :class="openSideBar ? 'upper-with-side-bar' : 'upper'" v-show="!heading">
       <el-button type="primary" icon="el-icon-arrow-up" @click="upper" circle> </el-button>