React Console Errors on RS School Platform

[stardustmeg]

Description

React errors are appearing in the browser console when accessing various pages on the RS School platform, affecting the user experience and potentially causing functionality issues.

Steps to reproduce the behavior:

1. Navigate to https://app.rs.school/
2. Open browser developer tools (F12)
3. Check the Console tab for errors
4. Also test on: https://app.rs.school/registry/mentor

Expected behavior:

• No React errors in browser console
• Clean console output without warnings or errors
• Stable platform functionality across all pages

Actual behavior:

React errors appearing in browser console:

• https://react.dev/errors/418?invariant=418
• https://reactjs.org/docs/error-decoder.html?invariant=423

Screenshots:

• Console tab showing React error #418 and React error #423

Device:

• Location: Belarus
• OS: Windows 11
• Browser: Google Chrome Version 141
• Time zone: UTC+3

Related URLs:

• Affected pages:
  • https://app.rs.school/
  • https://app.rs.school/registry/mentor
• Error references:
  • https://react.dev/errors/418?invariant=418
  • https://reactjs.org/docs/error-decoder.html?invariant=423

Additional context:

These console errors appear consistently across multiple pages and may indicate underlying React component or state management issues affecting the platform stability.

[emp74ark]

It is probably failed access to the api/registry/mentor from the client MentorRegistryService.

[emp74ark]

This error happens when a client tries to get mentor info from the mentor registry (client/src/services/mentorRegistry.ts:89). If there is no information for the user with such an ID, the API (koa) returns a 404 error (server/src/routes/registry/index.ts:59).

So, it is actually not a bug.

[emp74ark]

One hole closed, but the error still persists.

Another suspect is an ActiveCourseContext, which might return {} as a default value for the course field. PageLayout is wrapped with ActiveCourseContext and tried to get access to the course in the nested Header via useActiveCourseContext. Hook returns an empty object before the real value is resolved. Hook is broadly used in the app, and changing it might be challenging.

Additionally, the error happened, for example, in the 404 page and didn't happen in the cv/edit page.

One more PR with potential solution: #2888