> Perl's hashes are a complete mystery to me still

They're unordered mappings from strings to arbitrary values ("scalars" in Perl jargon). In this sense they're just like an object in JavaScript.

Where this gets a little weird is that Perl arrays and hashes are fundamental types distinct from scalars - you can't put a hash into a $variable without taking a reference to it first, for instance. But that's more a matter of Perl being picker about the value/reference distinction than a hash-specific thing.