[bcheung]

I'm wondering whether types would be required to implement static analysis to see if a particular scenario in the match is not handled. Haskell has the ability to generate a compile error if you don't have a match specified for each possible permutation. This makes it easy to make sure you handle all possible inputs. This probably wouldn't be possible in JS. Probably the best that could be done would be if the default matcher was left off.

[emodendroket]

The example seems to be a dictionary, so of course you cannot guarantee that all possible permutations are covered.