Fix: app crashed on open with no error — unguarded Intl call at render time

Intl.DateTimeFormat().resolvedOptions().timeZone ran as a bare destructuring
default with no try/catch, unlike every other side-effecting call in this
file (theme fetch, AsyncStorage, polling). Some release-mode Hermes builds
ship without full Intl support, so accessing it there throws — and since
this runs at render time before any error boundary exists, it's an uncaught
fatal with no red-box/dev-menu output, which matches "crashes on open, no
error, sudden exit" exactly (only reproduces in release builds, not debug,
since debug has Metro's overlay to at least surface something).

Wrapped it in a helper that falls back to "UTC" on any failure — same
fallback behavior AsyncStorage/theme-fetch already use elsewhere in this
file.

Author: tharindu20118

dist/useChattyChat.js

@@ -3,17 +3,28 @@ import AsyncStorage from "@react-native-async-storage/async-storage";
 import { ChattyClient, } from "./api";
 import { getOrCreateSessionId, newSession } from "./session";
 const MSGS_KEY = (botId, host) => `chatty_msgs_${botId}_${host}`;
+// Real IANA zone (e.g. "Asia/Colombo"), not a literal "UTC" default — the assistant uses
+// this to skip asking the visitor for their timezone (see widget_brain.py's scheduling
+// prompt), same as the web widget already does via the same Intl call. Guarded because
+// some release-mode Hermes builds ship without full Intl.DateTimeFormat support — this ran
+// unguarded as a destructuring default (i.e. at render time, outside any try/catch) and a
+// throw there is an uncaught render-time exception with no JS error boundary to catch it,
+// which crashes the whole app on open with no visible error.
+function _detectTimezone() {
+    try {
+        return Intl.DateTimeFormat().resolvedOptions().timeZone || "UTC";
+    }
+    catch {
+        return "UTC";
+    }
+}
 /**
  * Drives a full Chatty conversation: loads bot theme/config, manages the
  * persistent session id, sends messages, and polls for human-agent replies.
  * This is the native-SDK equivalent of widget.js's embed iframe lifecycle.
  */
 export function useChattyChat(options) {
-    // Real IANA zone (e.g. "Asia/Colombo"), not a literal "UTC" default — the assistant uses
-    // this to skip asking the visitor for their timezone (see widget_brain.py's scheduling
-    // prompt), same as the web widget already does via the same Intl call. Available in both
-    // Hermes and JSC on RN 0.72+ (this SDK's minimum).
-    const { botId, baseUrl, host, hostKey = "app", pollIntervalMs = 4000, visitorTimezone = Intl.DateTimeFormat().resolvedOptions().timeZone, } = options;
+    const { botId, baseUrl, host, hostKey = "app", pollIntervalMs = 4000, visitorTimezone = _detectTimezone(), } = options;
     const currentClient = useMemo(() => new ChattyClient({ botId, baseUrl, host }), [botId, baseUrl, host]);
     const clientRef = useRef(currentClient);
     clientRef.current = currentClient;

src/useChattyChat.ts

@@ -42,19 +42,30 @@ export interface UseChattyChatResult {
   clearChat: () => Promise<void>;
 }
 
+// Real IANA zone (e.g. "Asia/Colombo"), not a literal "UTC" default — the assistant uses
+// this to skip asking the visitor for their timezone (see widget_brain.py's scheduling
+// prompt), same as the web widget already does via the same Intl call. Guarded because
+// some release-mode Hermes builds ship without full Intl.DateTimeFormat support — this ran
+// unguarded as a destructuring default (i.e. at render time, outside any try/catch) and a
+// throw there is an uncaught render-time exception with no JS error boundary to catch it,
+// which crashes the whole app on open with no visible error.
+function _detectTimezone(): string {
+  try {
+    return Intl.DateTimeFormat().resolvedOptions().timeZone || "UTC";
+  } catch {
+    return "UTC";
+  }
+}
+
 /**
  * Drives a full Chatty conversation: loads bot theme/config, manages the
  * persistent session id, sends messages, and polls for human-agent replies.
  * This is the native-SDK equivalent of widget.js's embed iframe lifecycle.
  */
 export function useChattyChat(options: UseChattyChatOptions): UseChattyChatResult {
-  // Real IANA zone (e.g. "Asia/Colombo"), not a literal "UTC" default — the assistant uses
-  // this to skip asking the visitor for their timezone (see widget_brain.py's scheduling
-  // prompt), same as the web widget already does via the same Intl call. Available in both
-  // Hermes and JSC on RN 0.72+ (this SDK's minimum).
   const {
     botId, baseUrl, host, hostKey = "app", pollIntervalMs = 4000,
-    visitorTimezone = Intl.DateTimeFormat().resolvedOptions().timeZone,
+    visitorTimezone = _detectTimezone(),
   } = options;
 
   const currentClient = useMemo(() => new ChattyClient({ botId, baseUrl, host }), [botId, baseUrl, host]);