fix(auth): prevent logout audit from blocking redirect

src/lib/logoutFlow.ts

@@ -0,0 +1,47 @@
+const KEYCLOAK_LOGOUT_PATH = "/api/auth/keycloak-logout";
+
+type CompleteLogoutOptions = {
+  reportAudit: () => Promise<unknown>;
+  clearLocalState: () => void;
+  navigate: (path: string) => void;
+};
+
+type LogoutAuditOptions = {
+  endpoint: string;
+  accessToken?: string | null;
+  fetcher?: typeof fetch;
+};
+
+export const reportLogoutAudit = ({
+  endpoint,
+  accessToken,
+  fetcher = fetch,
+}: LogoutAuditOptions) => {
+  const headers = new Headers({ "Content-Type": "application/json" });
+  if (accessToken) {
+    headers.set("Authorization", `Bearer ${accessToken}`);
+  }
+
+  return fetcher(endpoint, {
+    method: "POST",
+    headers,
+    body: JSON.stringify({ event: "logout" }),
+    keepalive: true,
+  });
+};
+
+export const completeLogout = async ({
+  reportAudit,
+  clearLocalState,
+  navigate,
+}: CompleteLogoutOptions) => {
+  try {
+    void reportAudit().catch(() => undefined);
+  } catch {
+    // Synchronous reporting errors must not block logout either.
+  }
+
+  clearLocalState();
+  navigate(KEYCLOAK_LOGOUT_PATH);
+  return { success: true as const };
+};