[nanomonkey]

I'm pretty sure that JSON does not have a well defined serialization pattern between languages. If you rely on ECMAscript 6 (ES6) engine, then folks in other languages will have to reproduce the quirks of how serialization is done there to verify and reproduce hashes.

[kentonv]

Heh, I guess in my comment I was only thinking about how to make sure two different values don't end up with the same serialization, but indeed if you aren't careful then there is also the problem of two identical values ending up with different serializations, e.g. because you used a different JSON encoder or the field order was inconsistent.