Add web front-end and fix API issues

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

@@ -0,0 +1,8 @@
+import { Observable } from '../Observable';
+import { isFunction } from '../util/isFunction';
+export function throwError(errorOrErrorFactory, scheduler) {
+    const errorFactory = isFunction(errorOrErrorFactory) ? errorOrErrorFactory : () => errorOrErrorFactory;
+    const init = (subscriber) => subscriber.error(errorFactory());
+    return new Observable(scheduler ? (subscriber) => scheduler.schedule(init, 0, subscriber) : init);
+}
+//# sourceMappingURL=throwError.js.map