After hours of debugging, I found out where is a problem.
PostsRouter is name of router in the code, when it gets precompiled, name of class is changed to "n", which is bad because in constructor I have this code below
this.constructor.toString().match(/function\s*(\w+)/)
So I get wrong class name, but that's still OK. Then I'm doing this:
new App.Collections["" + this.class_name + "Collection"]
and that's the problem. App.Collections.nCollection not exists, correct name is App.Collections.PostsCollection.
I fix it by adding string literal into class definition, instead of parsing from constructor name.
Have a nice day!