So here we have :req and :opt to be used in s/keys. That doesn’t stop other keys tht are not listed in opt or req from being accepted right? How do you limit the keys that can be accepted to only the req and opt keys?

Let’s say I’m trying to conform a map to a spec. I want each key of the map to have values of a certain type. How can I write a spec for that?

I have this:

(s/def ::create-sessions-params (s/and (s/keys :opt-un [::students ::start_date ::start_time ::timezone ::instructor])))

but then for each key, I want to impose a type to the key’s value too

how will I do that?

(s/def ::instructor string?) etc.

(the s/and in your example doesn't do anything - remove it)

I can read your question in several ways, might want to elaborate

@ghadi what would be the best way to restrict the keys to just the keys in the opt?

?

restrict what?

like it shouldn’t conform if there are keys other than the ones in the :opt-un list

opt-un or req-un or opt or req

same answer as in the thread above - transform lightly, then check

select-keys or similar

can I use one of these libraries to achieve the effect rather than select keys: https://github.com/metosin/spec-tools https://github.com/wilkerlucio/spec-coerce

So would this be good?:

(defn keys-conform? [m k]
 (every? (set k) (keys m)))
(def create-sessions-keys [::students ::start_date ::start_time ::timezone ::instructor])
(s/def ::create-sessions-params (s/and (s/keys :opt-un create-sessions-keys) #(keys-conform? % create-sessions-keys)))

keys-conform makes sure that the keys in the map are only the ones that are in the keys vector

s/keys is a macro and cannot be passed a var like that, as I recall.

unfortunately, that won't work in s/keys

so you'd have to repeat the vector of keys there

btw, there is a faq entry about this here: https://clojure.org/guides/faq#exclusive_keys

What we do is get the spec form (via the Spec API) and lift the keys out of it to use in other contexts -- we treat the Spec itself as the "system of record".

@seancorfield can you please elaborate?

user=> (s/def ::f (s/keys :req [:a/x]))
:user/f
user=> (s/form ::f)
(clojure.spec.alpha/keys :req [:a/x])
user=>

you use s/form to inspect specs