supabase-js uses the cross-fetch library to make HTTP requests, which has issues on Cloudflare Workers. To solve this we can use Cloudflare Workers' in-built fetch method to make HTTP requests using the optional fetch parameter in the supabase-js client.

Source: https://supabase.com/docs/reference/javascript/initializing#custom-fetch-implementation

Credits

This example was originally created by @nascode.