500 error upon deployment of a Supabase subscription to Cloudflare Pages

Bug report

Describe the bug

I have a SvelteKit app that uses the ‘@sveltejs/adapter-cloudflare’ adapter to deploy to Cloudflare Pages.

The app uses the @supabase/supabase-js library to connect to my Supabase project. I’ve deployed an app with data reading & writing successfully to Supabase.

I’ve added a basic supabase subscription, and having deployed the change I get the following error on page load:

500 Cannot assign to read only property ‘stack’ of object ‘’ TypeError: Cannot assign to read only property ‘stack’ of object ‘’

The subscription works correctly in local development, but fails when deployed.

Here is the code snippet that causes the failure:

const steps = readable(null, (set) => {
        supabase
            .from('steps')
            .select('*')
            .order('created_at')
            .then(({error, data}) => set(data))

        /* Code above here deploys successfully. Code below does not. */

        const subscrption = supabase
            .from('steps')
            .on('*', (payload) => {
                if (payload.eventType === 'INSERT') {
                    set([...get(steps), payload.new])
                }
            })
            .subscribe()
        return () => supabase.removeSubscription(subscrption)
    })

System information

• OS: Windows
• Browser (if applies): Chrome
• Version of supabase-js: 1.35.4
• Version of Node.js: 16

[w3b6x9]

@craigdrayton gotcha, i’ll close this issue for now but feel free to re-open if you’re hunch regarding CF adapter doesn’t work out.

[craigdrayton]

Well color me confused, when I do nothing other than add a try/catch block around the subscription, the 500 error stops occurring, but also the subscription works!?

const steps = readable(null, (set) => {
        supabase
            .from('steps')
            .select('*')
            .order('created_at')
            .then(({error, data}) => set(data))

        try {
            const subscrption = supabase
            .from('steps')
            .on('INSERT', (payload) => {
                set([...get(steps), payload.new])
            })
            .subscribe()

            return () => supabase.removeSubscription(subscrption)
        } catch(e) {
            console.log(e)
        }
    })