tools-only Put Interaction Logic in Event Handlers
If a side effect is triggered by a specific user action (submit, click, drag), run it in that event handler. Do not model the action as state + effect; it makes effects re-run on unrelated changes and can duplicate the action.
Incorrect (event modeled as state + effect):
function Form() {
const [submitted, setSubmitted] = useState(false)
const theme = useContext(ThemeContext)
useEffect(() => {
if (submitted) {
post('/api/register')
showToast('Registered', theme)
}
}, [submitted, theme])
return <button => setSubmitted(true)}>Submit</button>
}
Correct (do it in the handler):
function Form() {
const theme = useContext(ThemeContext)
function handleSubmit() {
post('/api/register')
showToast('Registered', theme)
}
return <button
}
Reference: Should this code move to an event handler?