React UseDebugValue

React useDebugValue

Created By: chatGPT

useDebugValue is a custom hook in React that helps you tag components with useful debug information. It's particularly helpful when you create custom hooks and want to expose specific values when inspecting components in tools like React DevTools. By using useDebugValue, you can make it easier to understand your app's state and behavior while debugging. Let's walk through a simple example of how to implement and use this hook.

import React, { useState, useDebugValue } from 'react';

function useFriendStatus(friendID) {
    const [isOnline, setIsOnline] = useState(null);

    // Simulating a subscription to a friend's status
    useEffect(() => {
        const handleStatusChange = (status) => {
            setIsOnline(status.isOnline);
        };

        // Imagine this is a subscription to some service
        const unsubscribe = fakeFriendStatusService.subscribe(friendID, handleStatusChange);

        return () => {
            unsubscribe();
        };
    }, [friendID]);

    // Use useDebugValue to show if the friend is online
    useDebugValue(isOnline ? 'Online' : 'Offline');

    return isOnline;
}

function FriendStatus({ friendID }) {
    const isOnline = useFriendStatus(friendID);
    return <div>{isOnline ? 'Friend is online' : 'Friend is offline'}</div>;
}

function App() {
    return <FriendStatus friendID={1} />;
}

In this example, we've created a custom hook called useFriendStatus that checks if a friend is online. Inside this hook, we utilize useDebugValue to provide a label for the online status. When examining this component in React DevTools, you will see the debug information indicating whether the friend is 'Online' or 'Offline'.

This way, useDebugValue serves as a powerful tool for assisting with debugging your custom hooks and understanding the component's behavior more clearly.

import React, { useEffect, useState } from 'react';

const fakeFriendStatusService = {
    subscribe(friendID, callback) {
        // Simulated subscription logic
        callback({ isOnline: true });
        return () => {}; // Simulated cleanup
    },
};