Refactor uploadFile to extract functionality

src/App.tsx

@@ -82,6 +82,15 @@ function downloadUri(uri: string, filename: string) {
   downloadAnchor.click();
 }
 
+async function eventToAsync<EventType extends keyof HTMLElementEventMap>(element: HTMLElement, eventType: EventType) {
+  const abortController = new AbortController();
+  const evt = await new Promise<HTMLElementEventMap[EventType]>((resolve) => {
+    element.addEventListener(eventType, (evt) => resolve(evt), {signal: abortController.signal});
+  })
+  abortController.abort();
+  return evt;
+}
+
 /**
  * This appears to be the best way to upload a file.
  */
@@ -89,14 +98,10 @@ async function uploadFile() {
   const uploadInput = document.createElement("input");
   uploadInput.type = "file";
   uploadInput.click();
-  const abortController = new AbortController();
-  await new Promise((resolve) => uploadInput.addEventListener("change", resolve, {signal: abortController.signal}));
-  abortController.abort();
+  await eventToAsync(uploadInput, "change");
   const files = uploadInput.files;
   if (files?.length !== 1) return;
-  const file = files[0];
-  console.log(file.name);
-  return file;
+  return files[0];
 }
 
 function App() {