How to wait for a hook to execute and then execute another synchronized function?

Question

React

I have a hook that updates the state of a pdf document

const [instance, update] = usePDF({ document: ShowPdf() })

I need to download the document only after the update happens, but since the hooks are asynchronous, I download the previous version of the document.
I know that you can use useEffect like this:
but then it will be loaded even after rendering, and I need it only when the button is pressed

useEffect(() => {
    downloadPdf()
  }, [instance])

Answer 1

Maybe add a banal if check?
useEffect(() => {
if(instance) {
downloadPdf()
}
}, [instance])