It might be worthwhile to have the `tinystan` code do some existence/type checking of the `data` parameter before attempting to read it at greater length. _Originally posted by @jsoules in https://github.com/flatironinstitute/stan-playground/issues/226#issuecomment-2445073258_ [General example](https://runjs.app/play/#Y29uc3QgZCA9IHtkYXRhIDogImZvbyJ9OwoKY29uc3QgZDIgPSB7ZGF0YTogdW5kZWZpbmVkfTsKCmNvbnN0IGQzID0ge307Cgpjb25zb2xlLmxvZyhkLCBkMiwgZDMpOwoKCmNvbnNvbGUubG9nKHsuLi5kLCAuLi5kMn0sIHsuLi5kLCAuLi5kM30p)