Expo with Supabase crashes on device but works on Expo Go

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04-10-2024

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Expo with Supabase: Why Your App Works in Expo Go but Crashes on Device?

Have you built an amazing Expo app using Supabase, only to see it crash when you try to run it on your physical device? This frustrating issue happens more often than you might think, leaving developers scratching their heads.

The Scenario:

You've built a fantastic Expo app using Supabase for authentication, data storage, or other functionalities. It works flawlessly in Expo Go, the development environment. However, when you build the app for a real device, it throws an error and crashes.

Original Code (Example):

import { useSupabaseClient } from '@supabase/supabase-auth-helpers';
import { useEffect, useState } from 'react';

const MyComponent = () => {
  const supabase = useSupabaseClient();
  const [user, setUser] = useState(null);

  useEffect(() => {
    const getProfile = async () => {
      const { data, error } = await supabase.auth.getUser();
      if (error) console.error(error);
      setUser(data?.user);
    };

    getProfile();
  }, [supabase]);

  return (
    // ... rest of your component code ...
  );
};

The Real Issue: Network Differences

The root of the problem lies in the significant difference in network behavior between Expo Go and a real device.

• Expo Go: Uses a development server within the app itself. This server is often on the same network as the device, resulting in a faster and more reliable connection to Supabase.
• Real Device: Directly interacts with the outside world, relying on cellular or Wi-Fi data. This can introduce significant latency and even network issues that are absent in Expo Go.

Understanding the Crash:

The crash often occurs when the app tries to connect to Supabase for the first time or during authentication. Here's why:

• Timeout Errors: The default timeout for network requests can be quite short. If your device has a slow network connection, the request might time out before it reaches Supabase.
• Server Response Handling: Sometimes, Supabase might respond with unexpected data or errors. A real device might have difficulty parsing this response compared to the more controlled environment of Expo Go.

Solutions:

1. Increase Network Timeouts:

   • Adjust your network timeout settings in Expo. You can achieve this by:
     • Manually setting timeouts in your code: Increase the timeout for your Supabase requests in the fetch or axios calls.
     • Using Expo's Network API: Access the Network API to modify default timeout settings.

2. Proper Error Handling:

   • Implement thorough error handling to gracefully deal with potential errors from Supabase.
   • Display informative error messages to the user if a network error occurs.

3. Cache and Offline Support:

   • Implement caching mechanisms to reduce the frequency of requests to Supabase.
   • Consider offline support to allow your app to work even without a stable internet connection.

4. Test on Multiple Networks:

   • Test your app on different network conditions (e.g., cellular, Wi-Fi, low bandwidth) to identify potential issues early.

5. Review Supabase Configuration:

   • Ensure your Supabase database settings are correctly configured in your Expo project.
   • Check for any limitations on your Supabase plan, particularly for data transfer or request limits.

Additional Tips:

• Use a Supabase SDK: Utilize the official Supabase SDK for Expo, which offers optimized network handling and error management.
• Use a Network Monitoring Tool: Employ a network monitoring tool like Charles Proxy to analyze network traffic and pinpoint the source of the problem.

Conclusion:

The difference between Expo Go and a real device's network environment is often the culprit behind Supabase crashes. By understanding the underlying issues and implementing appropriate solutions, you can overcome these challenges and build a robust, reliable Expo app using Supabase. Remember, patience and thorough testing are crucial to ensuring a seamless user experience across various devices and network conditions.