mobl::Map only works for simple key types, i.e. for types whose toString is a faithful representation of the instances. This includes String, Num, Bool, etc., but excludes object-like types like a Type or Entity. The reason is that key.toString is used to index the JS hash which fails for Types and Entities whose toString is always “[object Object]”.

Submitted by Meinte Boersma on 23 March 2012 at 14:32

This is probably becuase of the object toString,

did you try to define a toString function yourself for types?