React 19's useActionState Showed Me Why Disabling My Submit Button Was Never Enough

Every form I ever shipped before React 19 needed the same three pieces of state, and I wired them up by hand every single time.

One for the result. One for whether it's submitting. One for the error. And at least once a sprint, I'd forget to reset one of them in the right place and spend twenty minutes staring at a button that wouldn't re-enable.

Here's the version I wrote for years, probably the same one you have sitting in a dozen components right now:

function OldSignupForm() {

const [error, setError] = useState(null);