Add web front-end and fix API issues

node_modules/rxjs/dist/esm/internal/operators/count.js

@@ -0,0 +1,5 @@
+import { reduce } from './reduce';
+export function count(predicate) {
+    return reduce((total, value, i) => (!predicate || predicate(value, i) ? total + 1 : total), 0);
+}
+//# sourceMappingURL=count.js.map