How to handle a situation where props have been updated, but the previous request has not yet finished? How to avoid race conditions?

To avoid race conditions when updating props and performing asynchronous requests simultaneously, you can use the following approaches:

• Cancel previous requests. If the API supports cancellation (e.g., via AbortController in fetch), cancel the previous request when updating props.

const controller = new AbortController();

useEffect(() => {
  controller.abort(); // cancel previous request
  const newController = new AbortController();

  fetch(url, { signal: newController.signal })
    .then(response => response.json())
    .then(data => {
      // update state
    })
    .catch(err => {
      if (err.name === 'AbortError') return; // request was canceled
      // handle errors
    });

  return () => newController.abort();
}, [props]);

• Use a request counter or token. Increment a counter or generate a unique token for each new request, and upon receiving a response, check if it matches the latest request. If not, ignore the result.

• Local state to track relevance. For example, store the request identifier in state and update only if the response corresponds to the latest request.

These methods help prevent a situation where an old response overwrites data received from a newer request.