urql with Firebase Authentidation on Haxe/JS.

app.hx

    final client = UrqlReact.createClient({
        url: "http://localhost:8080/",
        requestPolicy: CacheAndNetwork,
        exchanges: [
            Urql.dedupExchange,
            Urql.cacheExchange,
            (input:ExchangeInput) -> {
                (ops:Source<Operation>) -> {
                    final auth = Authenticaton.getAuth(); //firebase authentication
                    pipe(
                        ops,
                        mergeMap((operation:Operation) -> {
                            final currentUser = auth.currentUser;
                            if (currentUser != null) {
                                fromPromise(currentUser.getIdToken(true).then(token -> {
                                    final fetchOptions = if (operation.context.fetchOptions == null) {
                                        ({} : RequestInit);
                                    } else if (Syntax.typeof(operation.context.fetchOptions) == "function") {
                                        (operation.context.fetchOptions : ()->RequestInit)();
                                    } else {
                                        (operation.context.fetchOptions : RequestInit);
                                    }

                                    final headers = new Headers(fetchOptions.headers);
                                    headers.set("Authorization", 'Bearer ${token}');

                                    Urql.makeOperation(operation.kind, operation, {
                                        additionalTypenames: operation.context.additionalTypenames,
                                        preferGetMethod: operation.context.preferGetMethod,
                                        suspense: operation.context.suspense,
                                        meta: operation.context.meta,
                                        url: operation.context.url,
                                        requestPolicy: operation.context.requestPolicy,
                                        fetchOptions: {
                                            // headers: headers, <- not work
                                            headers: {
                                                "Authorization": 'Bearer ${token}'
                                            },
                                            body: fetchOptions.body,
                                            cache: fetchOptions.cache,
                                            credentials: fetchOptions.credentials,
                                            integrity: fetchOptions.integrity,
                                            method: fetchOptions.method,
                                            mode: fetchOptions.mode,
                                            observe: fetchOptions.observe,
                                            redirect: fetchOptions.redirect,
                                            referrer: fetchOptions.referrer,
                                            referrerPolicy: fetchOptions.referrerPolicy,
                                            signal: fetchOptions.signal
                                        },
                                        fetch: operation.context.fetch
                                    });
                                }));
                            } else {
                                ops;
                            }
                        }),
                        input.forward
                    );
                }
            },
            Urql.fetchExchange
        ]
    });