Add web front-end and fix API issues

node_modules/rxjs/dist/esm5/internal/firstValueFrom.js

@@ -0,0 +1,24 @@
+import { EmptyError } from './util/EmptyError';
+import { SafeSubscriber } from './Subscriber';
+export function firstValueFrom(source, config) {
+    var hasConfig = typeof config === 'object';
+    return new Promise(function (resolve, reject) {
+        var subscriber = new SafeSubscriber({
+            next: function (value) {
+                resolve(value);
+                subscriber.unsubscribe();
+            },
+            error: reject,
+            complete: function () {
+                if (hasConfig) {
+                    resolve(config.defaultValue);
+                }
+                else {
+                    reject(new EmptyError());
+                }
+            },
+        });
+        source.subscribe(subscriber);
+    });
+}
+//# sourceMappingURL=firstValueFrom.js.map