add map-key

CHANGES.md

@@ -1,6 +1,7 @@
 ## 1.0.2-SNAPSHOT
 
 * Added `pred=`, `pred<`, `pred>`, `pred<=`, `pred>=` for filtering using common comparisons
+* Add `map-key` navigator
 
 ## 1.0.1
 

src/clj/com/rpl/specter.cljc

@@ -868,6 +868,20 @@
                                         )))
                             structure)))))
 
+(defrichnav
+  ^{:doc "Navigates to the given key in the map (not to the value). Navigates regardless
+          of whether the key currently exists in the map. For transforms, will assoc nil
+          value if key doesn't currently exist in map."}
+  map-key
+  [key]
+  (select* [this vals structure next-fn]
+    (next-fn vals key))
+  (transform* [this vals structure next-fn]
+    (let [newkey (next-fn vals key)
+          oldval (get structure key)]
+      (-> structure (dissoc key) (assoc newkey oldval))
+      )))
+
 (def ^{:doc "Navigate to the specified keys one after another. If navigate to NONE,
              that element is removed from the map or vector."}
   keypath

test/com/rpl/specter/core_test.cljc

@@ -1527,6 +1527,11 @@
     (is (= [3 4] (select [s/ALL (s/pred>= 3)] data)))
     ))
 
+(deftest map-key-test
+  (is (= {:b nil :c 3} (setval (s/map-key :a) :b {:c 3})))
+  (is (= {:b 2} (setval (s/map-key :a) :b {:a 2})))
+  )
+
 #?(:clj
   (do
     (defprotocolpath FooPP)