[aryanpatil-07]

fix: Prevent TypeError crash when login API returns undefined

Acceptance Criteria fulfillment

• Prevent unhandled TypeError: Cannot read properties of undefined (reading 'error') when RCInstance.login returns undefined.
• Add guard check to display a user-friendly error toast message when the server is unreachable or offline.
• Verify local build and linting checks pass with zero regression.

Note: This bug was discovered and fixed directly during local development while testing offline/unreachable server scenarios.

Video/Screenshots

PR Test Details

1. Run the development server without a local Rocket.Chat backend running on port 3000.
2. Attempt to submit credentials in the login dialog.
3. Observe that instead of an uncaught TypeError in the browser console, a clean error toast notification is displayed informing the user that the server is unreachable.

Note: The PR will be ready for live testing at https://rocketchat.github.io/EmbeddedChat/pulls/pr-1393 after approval. Contributors are requested to replace <pr_number> with the actual PR number.

[CLAassistant]

All committers have signed the CLA.

[Aryan-Verma-999]

Could you please add a short demo video showing the offline/unreachable-server login flow and confirming there is no console TypeError?

[aryanpatil-07]

Hi @Aryan-Verma-999,

Thanks for reviewing! Here is a short demo video showing the unreachable-server login attempt with DevTools open side-by-side:

Screen.Recording.2026-10-23.160037.mp4

As shown in the recording:

• The UI gracefully captures the network failure and displays the error toast message.
• The browser console logs the expected ERR_CONNECTION_REFUSED / Failed to fetch without throwing the previous unhandled TypeError: Cannot read properties of undefined (reading 'error').

Please let me know if any other adjustments are needed!

[Aryan-Verma-999]

Thanks for the demo. The guard removes the secondary TypeError, but the underlying issue is that EmbeddedChatApi.login() catches non-401/network errors and implicitly returns undefined.
Could you instead rethrow non-401 errors from login()? useRCAuth already catches thrown errors and displays the connection-error toast, so this keeps the API contract clear: it either returns a login result or throws.

[aryanpatil-07]

Hi @Aryan-Verma-999,

That makes total sense, keeping the API contract strict by either returning the login result or throwing is much cleaner.

I have updated EmbeddedChatApi.login() to rethrow non-401 errors so they propagate directly to useRCAuth's existing error handling, and reverted the UI-level guard check. Tested locally to verify that network errors cleanly trigger the connection toast without any unhandled TypeErrors.

Thanks for the feedback!