feat(assert): adds new assert-like functionality to check malli schema

src/malli/assert.cljc

@@ -0,0 +1,29 @@
+(ns malli.assert
+  (:refer-clojure :exclude [assert])
+  (:require
+   [malli.core :as m]
+   [malli.dev.pretty :as pretty]
+   [malli.util :as mu]))
+
+(def ^:dynamic *reporter* (pretty/thrower (pretty/-printer {:colors nil})))
+
+
+(defmacro assert
+  "Assert that `x` validates against schema `?schema`, or throws ExceptionInfo.
+   The clojure.core/*assert* constant controls whether assertion are checked."
+  ([?schema x]
+   (if *assert*
+     `(let [x# ~x]
+        (if (m/validate ~?schema x#)
+          x#
+          (*reporter* ::m/explain (mu/explain-data ~?schema x#))))
+     ~x)))
+
+
+;; -----------------------------------------------------------------------------------------------------------
+;; Developer Notes
+;;
+(comment
+  (assert int? "42")
+  (assert int? 42)
+  )

src/malli/dev/virhe.cljc

@@ -23,9 +23,11 @@
 
 (defn -color [color body printer]
   (let [colors (:colors printer -dark-colors)
-        color (get colors color (:error colors))]
+        color  (get colors color (:error colors))]
     #?(:cljs [:span body]
-       :clj  [:span [:pass (str "\033[38;5;" color "m")] body [:pass "\u001B[0m"]])))
+       :clj (if color
+              [:span [:pass (str "\033[38;5;" color "m")] body [:pass "\u001B[0m"]]
+              [:span body]))))
 
 ;;
 ;; EDN

test/malli/assert_test.cljc

@@ -0,0 +1,28 @@
+(ns malli.assert-test
+  (:refer-clojure :exclude [assert])
+  (:require
+   [clojure.test :refer [deftest is]]
+   [malli.assert :refer [assert]]))
+
+(deftest assert-throws-test
+  (is (= *assert* true))
+  (is (thrown? #?(:clj Exception, :cljs js/Error)
+               (assert :int "42" )))
+  (is (thrown? #?(:clj Exception, :cljs js/Error)
+               (assert int? "42" )))
+  (is (thrown? #?(:clj Exception, :cljs js/Error)
+               (assert string? 42)))
+  (is (thrown? #?(:clj Exception, :cljs js/Error)
+               (assert int? nil)))
+  (is (thrown? #?(:clj Exception, :cljs js/Error)
+               (assert [:map [:a int?]] {:a "42"})))
+  (is (thrown? #?(:clj Exception, :cljs js/Error)
+               (assert ::invalid-schema 42))))
+
+(deftest assert-checked-and-does-not-throw
+  (is (= *assert* true))
+  (is (= 42 (assert :int 42 )))
+  (is (= 42 (assert int? 42 )))
+  (is (= "42" (assert string? "42")))
+  (is (= nil (assert any? nil)))
+  (is (= {:a 42} (assert [:map [:a int?]] {:a 42}))))