chore(): migrate vue to typescript (#15928)

vue/src/api-utils.ts

@@ -0,0 +1,17 @@
+import { HTMLStencilElement } from './interfaces';
+
+// A proxy method that initializes the controller and calls requested method
+export function proxyMethod(tag: string, method: string, ...opts: any[]): Promise<any> {
+  return initController(tag).then((ctrl: any) => ctrl[method].apply(ctrl, opts));
+}
+
+// Initialize an Ionic controller and append it to DOM
+export function initController(tag: string): Promise<HTMLStencilElement> {
+  let element = document.querySelector(tag) as HTMLElement;
+
+  if (!element) {
+    element = document.body.appendChild(document.createElement(tag));
+  }
+
+  return (element as HTMLStencilElement).componentOnReady();
+}