Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
IMO this solution, while it works and short, is not a good practice:
the filtering function has its side effect (actually, that's the reason it works).
I think that filtering functions should not have side effects, so that we can move them around the code and reused them elsewhere.