React Form Handling: Debounced Validation, Auto-Save Drafts, and Controlled Inputs Forms are the most rewritten part of every React app. They look easy on day one — slap a <input> , wire onChange to useState , ship it. By month three, the same form has grown async username validation, an auto-saved draft, a custom date popover, and a controlled-or-uncontrolled toggle that has to play nicely with the design system. Each of those features pulls in its own ad-hoc state machine, its own effect cleanup, and its own pile of edge cases. The form file becomes the longest in the codebase, and nobody on the team wants to touch it. This post walks through four primitives that every non-trivial form needs eventually: a debounced value to throttle async validation, a controlled-or-uncontrolled wrapper that lets a component accept either pattern, a localStorage-backed draft that survives refreshes, and a click-outside detector that closes popovers without leaking listeners.…