Implement and test filter-keys and select-namespaced

src/swark/core.cljc

@@ -1,5 +1,6 @@
 (ns swark.core
-  (:require [clojure.string :as str]))
+  (:require [clojure.string :as str])
+  (:import [clojure.lang Named]))
 
 ;; SWiss ARmy Knife - Your everyday clojure toolbelt!
 ;; Copyright 2024 - Stan Verberkt ([email protected])
@@ -32,6 +33,30 @@
          (map (juxt key (comp f val)))
          (into {}))))
 
+(defn filter-keys
+  [map pred]
+  {:added "0.1.3"
+   :arglists '([map pred])
+   :doc "Returns a map containing only those entries in map whose key return logical true on evaluation of (pred key)."
+   :static true}
+  (cond->> map
+    pred    (filter (comp pred key))
+    map     seq
+    :always (into {})))
+
+(defn select-namespaced
+  {:added "0.1.3"
+   :arglist '([map] [map ns])
+   :doc "Returns a map containing only those entries in map whose keys' namespace match ns. When ns is nil, returns a map containing only non-namespaced keys."
+   :static true}
+  ([map]
+   (select-namespaced map nil))
+  ([map ns]
+   (-> map map? assert)
+   (when-not (string? ns) (some->> ns (instance? Named) assert))
+   (let [predicate (if ns #{(name ns)} nil?)]
+     (filter-keys map (comp predicate namespace)))))
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Regarding strings
 

test/swark/core_test.clj

@@ -37,6 +37,23 @@
     (t/is (thrown? AssertionError (sut/map-vals nil m)))
     (t/is (nil? (sut/map-vals inc nil)))))
 
+(t/deftest filter-keys
+  (let [map {:user-id 1 :user/name "Username" ::test "Testdata"}
+        ns-str (namespace ::this)]
+    (t/are [result f] (= result (sut/filter-keys map f))
+      {:user-id 1}            (complement namespace)
+      {:user/name "Username"} (comp #{"user"} namespace)
+      {::test "Testdata"}     (comp #{ns-str} namespace)
+      {}                     (comp #{"unknown"} namespace))))
+
+(t/deftest select-namespaced
+  (let [map {:user-id 1 :user/name "Username" ::test "Testdata"}]
+    (t/are [result ns] (= result (sut/select-namespaced map ns))
+      {:user-id 1}            nil
+      {:user/name "Username"} "user"
+      {::test "Testdata"}     (namespace ::this)
+      {} "unknown")))
+
 (t/deftest ->str
   (t/are [result input] (= result (sut/->str input))
     "Hello, Swark!" "Hello, Swark!"