Building Type-Safe Dynamic Components with TypeScript's Advanced Features

The Problem: Handling Many Form Element Types Safely

When building FairForms, I ran into a problem that sounds simple on paper but quickly became a surprisingly complex design challenge:

How do I build a form builder where each input type (text, multiple choice, date picker, etc.) has its own unique properties and behaviors, while preserving strict type safety and a smooth developer experience?

Let me unpack what I mean by preserving strict type safety and smooth developer experience, and why it matters.

In a dynamic UI system like a form builder with 15+ element types, it's easy to accidentally pass the wrong property or mutate data incorrectly, leading to subtle, hard-to-trace runtime bugs.