If I'm not mistaken, you can convert Malli schemas to JSONSchema, that could be the way to go I'm in the process of migrating my own solution where I have Prismatic Schema -> Avro -> Typescript types pipeline, and instead go with Malli -> JSONSchema to keep things simpler, but it's very early days

i'm in the sad position of not being able to use any clojure / clojurescript (yet)... but i can't imagine building anything resilient without the help of prismatic/spec or malli

I think Zod combined with TS is what most people use, I have a somewhat narrow view into the JS world but that's I've seen in the wild

but yes, "types at the edges" are a necessity in Clojure, just to maintain one's sanity ;-)

I remember trying out yup-ast at one point - https://github.com/WASD-Team/yup-ast

Maybe:

[:or 
  [:map [:a int?] [:b int?] [:c int?]]
  [:map [:a int?]]]

cf https://malli.io/?value=%7B%3Aa%201%7D&schema=%5B%3Aor%20%5B%3Amap%20%5B%3Aa%20int%3F%5D%20%5B%3Ab%20int%3F%5D%20%5B%3Ac%20int%3F%5D%5D%20%5B%3Amap%20%5B%3Aa%20int%3F%5D%5D%5D

It doesn't seem to translate properly to JSON Schema, mind you

Unfortunately no.

(malli.error/humanize 
 (malli.core/explain
  [:or
   [:map [:a int?] [:b int?] [:c int?]]
   [:map [:a int?]]]
  {:a 1
   :c 1}))
=> nil

This works if I’m willing to close the more minimal schema

[:or [:map [:a int?] [:b int?] [:c int?]] [:map {:closed true} [:a int?]]]

Interestingly, that generates not the expected JSON Schema, but it does generate a correct Swagger schema 🙂 https://malli.io/?value=%7B%3Aa%201%7D&schema=%5B%3Aor%20%5B%3Amap%20%5B%3Aa%20int%3F%5D%20%5B%3Ab%20int%3F%5D%20%5B%3Ac%20int%3F%5D%5D%20%5B%3Amap%20%7B%3Aclosed%20true%7D%20%5B%3Aa%20int%3F%5D%5D%5D

What’s wrong with its JSON Schema?

Doh! Nothing. I misread 😂