A Custom React Hook that handles duplicate API call

Today, we are going to create a custom hook that solve this problem:

We have multiple components that calling same API.
Component may not always be on same page, therefore, they have to call the API by themselves.

Here is a example hook I think can handle this problem:

let isCalling = new Map(); // This can be replace by some global state. I use this for the sake of simplicity.
function useFetch(url) {
  const [data, setData] = useState("");
  useEffect(() => {
    let isThisAPICalling = isCalling.get(url);
    if (!isThisAPICalling) {
      console.log("new");
      isThisAPICalling = fetch(url).then((response) => response.json());
      isCalling.set(url, isThisAPICalling);
      // The body can only be parsed once.
    }
    isThisAPICalling.then((json) => {
      console.log("done");
      console.log(json.title);
      isCalling.delete(url);
      setData(json.title);
    });
  }, []);
  return data;
}

Here is a demo.

Thank you all! Please let me know if you have any suggestion.

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A Custom React Hook that handles duplicate API call

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