Why can't symbolic keys be stringified?

[hrueger]

Hi,
I'm using SvelteKit together with Prisma with computed fields. Results cannot be stringified and sent to the client (in load for example), because that throws this error:

Cannot stringify POJOs with symbolic keys

Interestingly, if I just comment out those checks here and here, it works just fine. Is there a reason for this check and some edge cases I haven't yet ran into?

Thanks in advance.

For anyone wanting to test, here's a patchfile for yarn patch: devalue-npm-4.3.2-e483100d94.patch