Add TypeScript types for controllers

**Problem**
When working with components, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

The issue names controllers and components but does not identify files, tests, or an entry point. First clarify whether the work is to add TypeScript types for controllers, improve component error messages, or both; done should include an agreed scope and a way to verify the resulting types or error handling.

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