[BUG] Activity registry returns undefined for unknown IDs instead of throwing, causing silent TypeError downstream

[anshul23102]

Description

src/registry/ (or src/data/activities/index.js) looks up activity definitions by ID using a plain object map. When a route is accessed with an unknown activity ID (e.g., a stale bookmark or a typo in a link), the lookup returns undefined. The consuming component then accesses undefined.title, throwing a TypeError that bubbles up uncaught and crashes the route.

Steps to Reproduce

1. Navigate to /activities/nonexistent-id in the running app.
2. Observe the component crashes with TypeError: Cannot read properties of undefined (reading 'title').
3. Confirm no 404 or fallback page is rendered - just a blank or broken UI.

Root Cause

The registry lookup has no guard for missing keys, and the route component does not check for a null/undefined result before rendering.

Impact

Any stale or manually crafted URL with an invalid activity ID crashes the route silently instead of showing a user-friendly 404 page.

Proposed Fix

// src/registry/index.ts
export function getActivity(id: string) {
  const activity = activityMap[id];
  if (!activity) throw new Response("Not found", { status: 404 });
  return activity;
}

Use React Router's errorElement on the route to render a 404 page when the loader throws.

[anshul23102]

@singhtrivendra Hi! I came across this issue and I would love to work on it as part of GSSoC '26.

I have reviewed the problem description carefully and am confident I can deliver a well-tested, production-ready fix within the contribution timeline. Please let me know if you need any additional context or have specific implementation preferences before I get started.

Could you please assign this issue to me?

/assign
/claim