有棱角的Javascript动画使用ng-if，但不使用ng-show

I've been experimenting with angular animations and have come to the conclusion that Angular JavaScript based animations are not triggered using ng-if. I developed a simple Plunkr demonstrating the inconsistency. Essentially, the problem with this is I don't want to be appending and removing elements from the DOM (ng-if) and would rather use ng-show because one of the items being animated is an HTML5 video that I would like to begin pre-loading upon page load. The code from the Plunkr is as follows:I've been experimenting with angular animations