fix(Sticky): shoud rerender after visibility changed (#5888)

src/sticky/index.js

@@ -7,11 +7,16 @@ const [createComponent, bem] = createNamespace('sticky');
 
 export default createComponent({
   mixins: [
-    BindEventMixin(function(bind) {
+    BindEventMixin(function(bind, isBind) {
       if (!this.scroller) {
         this.scroller = getScroller(this.$el);
       }
 
+      if (this.observer) {
+        const method = isBind ? 'observe' : 'unobserve';
+        this.observer[method](this.$el);
+      }
+
       bind(this.scroller, 'scroll', this.onScroll, true);
       this.onScroll();
     }),
@@ -58,6 +63,21 @@ export default createComponent({
     },
   },
 
+  created() {
+    // compatibility: https://caniuse.com/#feat=intersectionobserver
+    if (window.IntersectionObserver) {
+      this.observer = new IntersectionObserver(
+        entries => {
+          // trigger scroll when visibility changed
+          if (entries[0].intersectionRatio > 0) {
+            this.onScroll();
+          }
+        },
+        { root: document.body }
+      );
+    }
+  },
+
   methods: {
     onScroll() {
       if (isHidden(this.$el)) {