Empty schema causing errors because _schema is undefined

[LelouBil]

Hello, I was having a strange error while creating a room and I managed to narrow it down to having an empty schema class.

TypeError: Invalid value used in weak set in line 68 of SchemaSerializer.js, in the hasFilter function.

I'm not familiar enough with the code to submit a pr but I managed to found this while investigating the issue.

knownSchemas.add(schema); was giving the error because schema was undefined, because _schema of the class was undefined.

I tried adding a random property to my schema and _schema got defined.

I think an empty schema should have {} instead of undefined for _schema.

I don't actually know when or why it was undefined so I'm reporting the issue here.

[endel]

Hi @LelouBil, thanks for reporting. Version 0.14 of Colyseus is coming soon, along with an updated version of @colyseus/schema that should fix this, along with many other issues (#75, #82)