Val Town is a server-side platform, primarily: when you run code, it runs on a server. This has many benefits, like the ability to import many different modules, make requests to other servers, run code on a schedule, and much more.
However, there are some objects that aren’t really translatable from one
environment to another, like
Symbol objects. In some cases as well, code that returns data with recursive structures - self-references -
will fail to be serialized, and produce an error.