Using zoom in angular Leaftlet Directive inside ionic

I'm trying to use this library https://github.com/tombatossals/angular-leaflet-directive/ namely this example:

http://tombatossals.github.io/angular-leaflet-directive/examples/markers-simple-example.html

The problem is to run the same code inside of ionic, by some reason zoom is not applied and always used default one

Any idea why?