perf:滚动条出现的逻辑修复

src/components/Article.vue

@@ -179,7 +179,7 @@
             border: rgba(0, 0, 0, 0);
           "
         >
-          <div id="topiconid">
+          <div v-if="topShow">
             <el-button
               @click="toTop"
               type="info"
@@ -281,22 +281,23 @@ export default {
         }
     },
     watch: {
-        topShow: function (newvalue, oldvalue) {
-            if (newvalue === true) {
-                document.getElementById('topiconid').style.display = 'none'
-            } else {
-                document.getElementById('topiconid').style.display = 'block'
-            }
+        topShow: {
+            handler (newValue) {
+                if (newValue) {
+                    console.warn(newValue)
+                }
+            },
+            immediate: true
         }
     },
     beforeDestroy () {
-        window.removeEventListener('onload', this.topVisible())
+        // window.removeEventListener('onload', this.topVisible())
         this.articleScrollListen('remove')
     },
     mounted () {
         this.articleScrollListen('add')
         this.initPageSpliteFun()
-        window.addEventListener('onload', this.topVisible())
+        // window.addEventListener('onload', this.topVisible())
     },
     methods: {
         /**
@@ -304,13 +305,14 @@ export default {
        */
         articleScrollListen (key) {
             const dom = this.$refs['mark-down-ref']
+            const that = this
             if (dom && key === 'add') {
                 dom.addEventListener('scroll', function (e) {
-                    this.topShow = e.scrollTop > 0
+                    that.topShow = Math.ceil(e.target.scrollTop) !== 0
                 })
             } else if (dom && key === 'remove') {
                 dom.removeEventListener('scroll', function (e) {
-                    this.topShow = e.scrollTop > 0
+                    that.topShow = e.target.scrollTop === 0
                 })
             }
         },
@@ -376,9 +378,9 @@ export default {
             this.$store.commit('increment')
         },
         topVisible: function () {
-            let dom = document.getElementById('homeTitleId')
-            this.topShow = this.elementIsVisibleInViewport(dom)
-            setTimeout(this.topVisible)
+            // let dom = document.getElementById('homeTitleId')
+            // this.topShow = this.elementIsVisibleInViewport(dom)
+            // setTimeout(this.topVisible)
         },
         elementIsVisibleInViewport: function (el, partiallyVisible = false) {
             try {