Added missing type declarations and changed vue init

src/main.ts

@@ -1,14 +1,16 @@
 import Vue from "vue";
 import App from "@/App.vue";
-import VueCompositionApi from "@vue/composition-api";
+import VueCompositionApi, { createApp, h } from "@vue/composition-api";
 
-Vue.use(VueCompositionApi)
+Vue.use(VueCompositionApi);
 
 import "windi.css";
 
 Vue.config.productionTip = false;
 Vue.config.devtools = true;
 
-new Vue({
-  render: (h) => h(App),
-}).$mount("#app");
+const app = createApp({
+  render: () => h(App),
+});
+
+app.mount("#app");

src/shims-tsx.d.ts

@@ -0,0 +1,13 @@
+import Vue, { VNode } from "vue";
+
+declare global {
+  namespace JSX {
+    // tslint:disable no-empty-interface
+    interface Element extends VNode {}
+    // tslint:disable no-empty-interface
+    interface ElementClass extends Vue {}
+    interface IntrinsicElements {
+      [elem: string]: any;
+    }
+  }
+}

src/shims-vue.d.ts

@@ -0,0 +1,4 @@
+declare module "*.vue" {
+  import Vue from "vue";
+  export default Vue;
+}