Unobtrusive JavaScript polyfill

[seanpdoyle]

Closes hotwired/turbo-rails#33.
Closes hotwired/turbo-rails#37.

When loaded alongside @rails/ujs, start it via Rails.start(), and
then declare the turbo:-prefixed events that
correspond to their ajax:-prefixed counterparts.

[seanpdoyle]

This is currently limited to a Functional test HTML fixture file. I struggled to declare the code within this <script> tag in an ESM/UMD module, and then optionally import it. Unfortunately, I was unable to figure it out.

If anyone could provide guidance, I'd prefer to declare something like:

export function startUjs(Rails: any) {
  const { delegate, disableElement, enableElement } = Rails

  delegate(document, Rails.linkDisableSelector,   "turbo:before-cache", enableElement)
  delegate(document, Rails.buttonDisableSelector, "turbo:before-cache", enableElement)
  delegate(document, Rails.buttonDisableSelector, "turbo:submit-end", enableElement)

  delegate(document, Rails.formSubmitSelector, "turbo:submit-start", disableElement)
  delegate(document, Rails.formSubmitSelector, "turbo:submit-end", enableElement)
  delegate(document, Rails.formSubmitSelector, "turbo:before-cache", enableElement)
}

// ...
import Rails from "..."
import { startUjs } from "@hotwire/turbo/ujs"

startUjs(Rails)

[sstephenson]

Don't think this belongs in Turbo itself.

[rainerborene]

@sstephenson Totally agree. rails-ujs is a past thing. For those who are interest, here's how you can accomplish almost the same behaviour using Stimulus and Hotwire: https://gist.github.com/rainerborene/644da1be59ecb4f6c4c9637abf2622e0