test(sidebar): add event listener lifecycle cleanup tests #465

[elcabasa]

Fix event listener cleanup in Sidebar to prevent listener leaks

#465

Summary

This PR audits the event listener lifecycle in src/shared/components/ui/sidebar.tsx and ensures that all listeners registered by the sidebar are properly cleaned up when the component unmounts.

The goal is to prevent potential memory leaks and unnecessary event listener accumulation during repeated mount/unmount cycles (for example, when navigating between dashboard pages), while preserving all existing sidebar behavior.

What Changed

Event listener audit

• Reviewed every addEventListener registration in sidebar.tsx.
• Verified that each listener has a corresponding removeEventListener in the appropriate useEffect cleanup.
• Ensured that the same callback reference is used for both registration and cleanup, preventing orphaned listeners caused by mismatched function identities.

Cleanup improvements

• Fixed any missing cleanup logic where necessary.
• Refactored listener callbacks where needed to maintain stable function identities without changing component behavior.
• Preserved existing resize, click-outside, and responsive sidebar interactions.

Test coverage

Added/updated tests to verify:

• Event listeners are properly removed when the sidebar unmounts.
• Repeated mount/unmount cycles do not accumulate listeners.
• addEventListener and removeEventListener are called with matching callback references.
• Existing sidebar functionality remains unchanged after the cleanup improvements.

Validation

Verified by running:

npm test -- Sidebar

Additionally confirmed that:

• Sidebar resize behavior is unchanged.
• Click-outside handling continues to work as expected.
• No regressions were introduced to the sidebar interaction flow.

Why This Change?

Without proper cleanup, event listeners can persist after a component unmounts, leading to:

• Memory leaks
• Duplicate event handling
• Performance degradation over time
• Difficult-to-debug UI behavior after repeated navigation

This PR ensures the sidebar cleans up after itself correctly while maintaining identical user-facing behavior.

Acceptance Criteria

• ✅ Every registered event listener has a matching cleanup.
• ✅ Listener removal uses the same callback identity as registration.
• ✅ Repeated mount/unmount cycles do not accumulate listeners.
• ✅ Sidebar resize and click-outside behavior remain unchanged.
• ✅ Test coverage added to prevent future regressions.

Security Impact

None.

This is a performance and correctness improvement focused on preventing event listener leaks without changing application behavior.