Setting the file. One moment.
Skill 03 · Vercel React Best Practices
Subchapter 3.8
rules/advanced-init-once.mdMarkdown958 BView on GitHub
Do not put app-wide initialization that must run once per app load inside useEffect([]) of a component. Components can remount and effects will re-run. Use a module-level guard or top-level init in the entry module instead.
Incorrect (runs twice in dev, re-runs on remount):
function Comp() {
useEffect(() => {
loadFromStorage()
checkAuthToken()
}, [])
// ...
}Correct (once per app load):
let didInit = false
function Comp() {
useEffect(() => {
if (didInit) return
didInit = true
loadFromStorage()
checkAuthToken()
}, [])
// ...
}