scrollTo doesn't work with debounce

[lougreenwood]

I have a scrollEventHandler which is debouncing the scroll events so that I can create a scrollEnd-like feature:

scrollable-view.hbs

<div
  data-test-scroll-container
  class="scrollable-view"
  {{!-- {{on "scroll" (action (optional @onScroll))}} --}}
  {{on "scroll" (action (optional @onScroll))}}
  {{on "scroll" (action "scrollEnd" @onScrollEnd)}}
  ...attributes
>
  <div data-test-scroll-content class="scrollable-view__content">
    {{yield}}
  </div>
</div>

scrollable-view.js

export default Component.extend({
  layout,
  tagName: '',

  actions: {
    scrollEnd(callback) {
      if (callback && typeof callback === 'function') {
        debounce(this, () => callback, 100, false);
      }
    },
  },
});

This all works fine in the app. However, when I attempt to test this feature and make use of the scrollTo helper, each scroll event forces the debounce to wait for it's timeout to expire and trigger (effectively nullifying the purpose of the debounce).

It seems that this is caused by the use of wait in the helper: https://github.com/cibernox/ember-native-dom-helpers/blob/master/addon-test-support/scroll-to.js#L16

Now, my question is whether it's possible for the helper to wait for the scroll event to occur in the browser without having to wait() for ember runloop (which is what seems to cause the debounce)?

[lougreenwood]

Just to followup, if I change the waitForScrollEvent function to the following, my tests are fixed and debounce is working again as expected:

async function waitForScrollEvent() {
  let waitForEvent = new RSVP.Promise(function(resolve) {
    rAF(resolve);
  });
  return await waitForEvent;
}

Perhaps calling wait could be optional flag, something like scrollTo(selector, 0, 100, false)?

[cibernox]

I'd like to add something. The repo is not that is unmaintained, but it was mostly an experiment to bikeshed the API of the so called Grand Testing Unification.

This addon was tested, the community receive it well and eventually ember-test-helpers adopted those helpers, with almost no changes: Ember Test Helpers API.

Not all helpers were moved there. scrollTo specifically wasn't but I think that it's worth proposing it and let the core team decide wether that helper makes sense.