foo.js

let pagesByLocationKey = {};

function ListPage(props) {
  const { key } = props.location
  const [page, setPage] = useState(pagesByLocationKey[key] ? pagesByLocationKey[key].page : 0)
  const [data, setData] = useState(pagesByLocationKey[key] ? pagesByLocationKey[key].data : null)

  useEffect(() => {
    if (!data) {
      fetchPage(page).then(data => {
        setData(data)
        pagesByLocationKey[key] = { page, data }
      })
    }
  }, [page])

  return (
    <div>
      <ul/>
      <button onClick={() => {
        setPage(page + 1)
      }}>Next Page</button>
    </div>
  )
}