Add web front-end and fix API issues

node_modules/rxjs/dist/esm5/internal/util/args.js

@@ -0,0 +1,15 @@
+import { isFunction } from './isFunction';
+import { isScheduler } from './isScheduler';
+function last(arr) {
+    return arr[arr.length - 1];
+}
+export function popResultSelector(args) {
+    return isFunction(last(args)) ? args.pop() : undefined;
+}
+export function popScheduler(args) {
+    return isScheduler(last(args)) ? args.pop() : undefined;
+}
+export function popNumber(args, defaultValue) {
+    return typeof last(args) === 'number' ? args.pop() : defaultValue;
+}
+//# sourceMappingURL=args.js.map