Clojure.spec coercion test

spec-coercion.clj

(ns spec-test.core
  (:require [clojure.spec :as s]))

(defn x-integer? [x]
  (if (integer? x)
    x
    (if (string? x)
      (try
        (integer/parseint x)
        (catch exception e
          :clojure.spec/invalid))
      :clojure.spec/invalid)))

(s/def ::user/name string?)
(s/def ::user/age (s/conformer x-integer?))

(s/def ::user (s/keys :req [::user/name ::user/age]))

(s/conform ::user {::user/name "juho" ::user/age 9001})
;; => {:user/name "juho", :user/age 9001}
(s/conform ::user {::user/name "juho" ::user/age "9001"})
;; => {:user/name "juho", :user/age 9001}
(s/conform ::user {::user/name "juho" ::user/age "x9001"})
;; => :clojure.spec/invalid

This is a helpful compared to the first example listed in https://clojuredocs.org/clojure.spec/conformer which is too cryptic for the uninitiated in my opinion.