Rails’ actioncable library is a bit immature compared to other implementations, so there are a lot of rough edges to work around. One of those is the basic createConsumer function.
If your app is running without a DOM (nodejs), the node_module @rails/actioncable is going to fight you.
The rails guides recommend this:
createConsumer('https://ws.example.com/cable')
But that function relies on having a global document that can create <a> tags, which you won’t have in many contexts (node, react-native, etc.)
Also, why does a websocket library depend on HTML anchor tags?
You can work around this limitation by explicitly using a ws or wss protocol:
createConsumer('ws://localhost:3000/cable')