Add web front-end and fix API issues

node_modules/rxjs/dist/esm/internal/observable/empty.js

@@ -0,0 +1,9 @@
+import { Observable } from '../Observable';
+export const EMPTY = new Observable((subscriber) => subscriber.complete());
+export function empty(scheduler) {
+    return scheduler ? emptyScheduled(scheduler) : EMPTY;
+}
+function emptyScheduled(scheduler) {
+    return new Observable((subscriber) => scheduler.schedule(() => subscriber.complete()));
+}
+//# sourceMappingURL=empty.js.map