Fix the issue of of empty array

Author: jchen042

package.json

@@ -1,6 +1,6 @@
 {
   "name": "vue-virtualised",
-  "version": "0.0.6",
+  "version": "0.0.7",
   "description": "Vue components developed by Vue.js 3.0 for efficiently rendering large scrollable lists and hierarchical data. vue-virtualised is able to render and update 1 million nodes within a few seconds in front-end.",
   "keywords": [
     "vue",

src/components/Base/VirtualisedBaseScroller.vue

@@ -149,11 +149,15 @@ export default defineComponent({
       `initialScrollIndex value ${initialScrollIndex.value} is not Number`
     );
     invariant(
-      initialScrollIndex.value >= 0,
+      !isNil(initialScrollIndex.value) ||
+        (!isNaN(Number(initialScrollIndex.value)) &&
+          initialScrollIndex.value >= 0),
       `initialScrollIndex value out of range: requested index ${initialScrollIndex.value} but minimum is 0`
     );
     invariant(
-      initialScrollIndex.value < data.value.length,
+      isNil(initialScrollIndex.value) ||
+        (!isNaN(Number(initialScrollIndex.value)) &&
+          initialScrollIndex.value < data.value.length),
       `initialScrollIndex value out of range: requested index ${
         initialScrollIndex.value
       } is out of 0 to ${data.value.length - 1}`

src/main.js

@@ -1,6 +1,6 @@
 import { createApp } from "vue";
-// import SimpleExample from "./examples/simple-example/SimpleExample.vue";
-import DemoExample from "./examples/demo-example/DemoExample.vue";
+import SimpleExample from "./examples/simple-example/SimpleExample.vue";
+// import DemoExample from "./examples/demo-example/DemoExample.vue";
 
-// createApp(SimpleExample).mount("#app");
-createApp(DemoExample).mount("#app");
+createApp(SimpleExample).mount("#app");
+// createApp(DemoExample).mount("#app");