Unlock the Power of Custom Hooks with useDebugValue

Enhancing Debugging with useDebugValue

useDebugValue is a built-in Hook that provides a more comprehensive debugging experience by offering additional information about the internal logic of custom Hooks within the React DevTools.

By installing the React DevTools as a standalone app or browser extension, you can unlock the full potential of this Hook.

Adding Descriptive Labels with useDebugValue

Consider a simplified custom fetch Hook:

function useFetch(url) {
  const [data, setData] = useState(null);
  const [error, setError] = useState(null);
  const [loading, setLoading] = useState(false);

  useEffect(() => {
    setLoading(true);
    fetch(url)
     .then(response => response.json())
     .then(data => setData(data))
     .catch(error => setError(error))
     .finally(() => setLoading(false));
  }, [url]);

  return { data, error, loading };
}

Without useDebugValue, the debug information is limited, making it difficult to read and understand.

With useDebugValue, you can add descriptive labels to your custom Hooks, making it easier to identify and debug issues:

function useFetch(url) {
  const [data, setData] = useState(null);
  const [error, setError] = useState(null);
  const [loading, setLoading] = useState(false);

  useDebugValue('Fetch Data', data);
  useDebugValue('Fetch Error', error);
  useDebugValue('Fetch Loading', loading);

  useEffect(() => {
    setLoading(true);
    fetch(url)
     .then(response => response.json())
     .then(data => setData(data))
     .catch(error => setError(error))
     .finally(() => setLoading(false));
  }, [url]);

  return { data, error, loading };
}

Leveraging useDebugValue for Better Debugging

The useDebugValue Hook can be used to log out various types of data, including numbers, strings, and objects.

The expanded DebugValue entry lists the outputs of the useDebugValue calls in the order they occur in the source code.

Limitations and Best Practices

While useDebugValue is a powerful tool, it’s essential to understand its limitations:

• You cannot use useDebugValue to log out conditional and nested data due to the Rules of Hooks.
• Using useDebugValue heavily in production code might impact performance negatively.

Improving useState Debugging

The useDebugValue Hook can also be used to improve debugging information for the useState Hook.

By creating a custom Hook that utilizes useDebugValue, you can add descriptive labels to state entries, making it easier to identify and debug issues:

function useDebugState(initialValue) {
  const [state, setState] = useState(initialValue);
  useDebugValue('State', state);
  return [state, setState];
}

This custom Hook can be used in place of the built-in useState Hook to provide more informative debugging information.