From 8a55ebccc035e344c42009ce35d42d65b87aa74b Mon Sep 17 00:00:00 2001
From: Michael Fogleman <michaelwfogleman@gmail.com>
Date: Mon, 11 Sep 2017 11:06:45 -0400
Subject: [PATCH] Document map-key.

---
 List-of-Navigators.md | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/List-of-Navigators.md b/List-of-Navigators.md
index 10f3edf..980b050 100644
--- a/List-of-Navigators.md
+++ b/List-of-Navigators.md
@@ -38,6 +38,7 @@
     - [if-path](#if-path)
     - [index-nav](#index-nav)
     - [keypath](#keypath)
+    - [map-key](#map-key)
     - [multi-path](#multi-path)
     - [must](#must)
     - [nil->val](#nil-val)
@@ -558,6 +559,33 @@ See also [must](#must)
 [0 :boo]
 ```
 
+## map-key
+
+`(map-key key)`
+
+Navigates to the given key in the map (not to the value).
+
+```clojure
+=> (select [(map-key :a)] {:a 2 :b 3})
+[:a]
+=> (setval [(map-key :a)] :c {:a 2 :b 3})
+{:b 3, :c 2}
+```
+
+Navigates only if the key currently exists in the map.
+
+```clojure
+=> (select [(map-key :z)] {:a 2 :b 3})
+[]
+```
+
+Can transform to NONE to remove the key/value pair from the map.
+
+```clojure
+=> (setval [(map-key :a)] NONE {:a 2 :b 3})
+{:b 3}
+```
+
 ## multi-path
 
 `(multi-path & paths)`