Super expression must either be null or a function

I’m not sure what this error means, but my babel just updated, and now stimulus throws this error.

import { Application } from "stimulus"
import EmailSignupController from "./controllers/email_signup_controller"

const application = Application.start()
// the offending line. Commenting this out stops the error.
application.register("email_signup", EmailSignupController)

I’m using "stimulus": "^1.1.1" and "@babel/core": "7.6.2". When I was on babel 7.5.5 things worked fine.

[javan]

Closing for now. Will reopen if you can trace this back to Stimulus. ✌️

[javan]

Happy to try if you can share an example repo (or .zip of one).