[V4] Custom transition in route change

Hello everyone.
I am using Ionic 4 with Angular.
I have a question about making custom transition between some of the pages in my app.
I looked into source of ionic nav controller and there is @Prop() animation?: AnimationBuilder; but I can’t find any type for that in Ionic angular to use.

LIne 56:

Anyone know how to pass my custom Animation to router?
Thanks!

Refresh, anyone tried that before?

Refresh, there must be some way to achieve custom transition ionic, otherwise its useless in more customised applications…