So I can fetch data on mount with no problem .. although I am curious.

​

what if the fetch api is updated on the backend.. how will my page re render and set the new data if I have ZERO dependencies like below ? Or does useEffect know to automatically update if the api is updated on the backend?

​

(using react version 16)

example below.

const [data, setData] = useState({})

useEffect(() => {

    fetch('some/url')
      .then((response) => response.json())
      .then((res) => setData(res));

}, [])

​

Also I've tried adding a dependency assuring that my data updates but now my useffect calls twice on mount..idk why.

const [data, setData] = useState({})

useEffect(() => {

    fetch('some/url')
      .then((response) => response.json())
      .then((res) => setData(res));

}, [data])

bottom line is, I want to have the fetch api with ZERO dependencies so that it will not render twice but still be able to update on api change. I just need it to mount once but update when it needs to . I need to be able to post to the backend and see the data show up immediately

​

Separate question: Why does useEffect with a dependency render twice ? and not once?