add warn if does not support IntersectionObserver

Author: huangshuwei

babel.config.js

@@ -1,5 +1,21 @@
 module.exports = {
     comments: false,
+    presets: [
+        [
+            "@babel/env",
+            {
+                targets: {
+                    ie: "10",
+                    edge: "17",
+                    firefox: "60",
+                    chrome: "67",
+                    safari: "11.1"
+                },
+                useBuiltIns: "usage",
+                corejs: "3.6.5"
+            }
+        ]
+    ],
     plugins: ["transform-vue-jsx"],
     /* presets: [["env", { modules: false }]], */
     env: {

src/index.jsx

@@ -55,6 +55,22 @@ export default {
             this.observer.observe(this.$el);
         },
 
+        // is support IntersectionObserver
+        isSupport() {
+            if (
+                !("IntersectionObserver" in window) ||
+                !("IntersectionObserverEntry" in window) ||
+                !(
+                    "intersectionRatio" in
+                    window.IntersectionObserverEntry.prototype
+                )
+            ) {
+                console.warn(
+                    "Your browser does not support IntersectionObserver!"
+                );
+            }
+        },
+
         // destroy observer
         destroyObserver() {
             if (this.observer) {
@@ -64,6 +80,7 @@ export default {
         }
     },
     mounted() {
+        this.isSupport();
         this.createObserver();
     },
     beforeDestroy() {