[v4] Ion-Slides appears to ignore the "effect" option

I’m trying to use the fade transition effect with the ion-slides component, but the option seems to be ignored when I do.

Ion-slides uses SwiperJS under the hood, with the documentation even referring to the swiperjs docs when referencing the options attribute.

These options include an “effect” parameter that enable different transition animations (swipe, cube, fade, etc).

When I try to use effect: "fade", nothing seems to happen. You can see for yourself in this test repository where I have added ion-slides to a starter application. The options I’m using are pulled directly from SwiperJS’s fade effect demo, seen working here.

If this is intentional, it should be clarified in Ionic’s documentation which options are actually usable and which are disabled. If it’s a bug, I hope that v4 is still receiving support.

[0] https://github.com/AndruC/ionic-slide-fade-test
[1] https://stackblitz.com/edit/swiper-demo-22-fade-effect?file=index.html