Add web front-end and fix API issues

node_modules/rxjs/dist/esm5/internal/observable/throwError.js

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