Do not wrap a simple expression with a primitive result type in useMemo
When an expression is simple (few logical or arithmetical operators) and has a primitive result type (boolean, number, string), do not wrap it in useMemo.
Calling useMemo and comparing hook dependencies may consume more resources than the expression itself.
Incorrect:
function Header({ user, notifications }: Props) {
const isLoading = useMemo(() => {
return user.isLoading || notifications.isLoading
}, [user.isLoading, notifications.isLoading])
if (isLoading) return <Skeleton />
// return some markup
}Correct:
function Header({ user, notifications }: Props) {
const isLoading = user.isLoading || notifications.isLoading
if (isLoading) return <Skeleton />
// return some markup
}