This is a basic proof-of-concept package that uses the _uihooks for Meteor Devel.
What it gives you is a basic {{#transition}}
helper -- which if you wrap around an {{#each}}
or a {{#if}}
will animate the removal / addition (and eventually movement) of elements using CSS Transitions.
Check out the basic-example for a simple usage.
You must have a transition defined for the element on the .off-screen
-> not .off-screen
class change. If you don't, there be dragons.
Eventually this will be a real package with options and the rest. Until then the best contribution is suggestions to what it needs. Perhaps it's perfect as is?