Or even skip the DSL and use JS for both client and server, just independently. Validation functions can/should be simple, pure JS that can be imported from both.
Validation logic is surprisingly simple but almost always lives in different domains. Unique columns are a great example, the validation has to happen at the database layer itself and whatever language is used to call it will just be surfacing the error.
Language and runtime decisions really need more context to be useful. JS everywhere can work well early on when making a small number of devs as productive as possible is a goal. When a project scales parts of the stack usually have different priorities take over that make JS a worse fit.
