From 9788f7101b1cd3e6ea5bda14704017615e3e03df Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Sat, 30 Jan 2016 17:54:39 -0800
Subject: [PATCH] Ensure fp `unset` is immutable. [closes #1913]

---
 fp/_mapping.js  | 3 ++-
 test/test-fp.js | 8 +++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/fp/_mapping.js b/fp/_mapping.js
index 4d7c1fd41..614ee876c 100644
--- a/fp/_mapping.js
+++ b/fp/_mapping.js
@@ -174,7 +174,8 @@ exports.mutate = {
   },
   'set': {
     'set': true,
-    'setWith': true
+    'setWith': true,
+    'unset': true
   }
 };
 
diff --git a/test/test-fp.js b/test/test-fp.js
index 7ac1344bd..cee1baa49 100644
--- a/test/test-fp.js
+++ b/test/test-fp.js
@@ -400,7 +400,7 @@
         deepObject = { 'a': { 'b': 2, 'c': 3 } };
 
     QUnit.test('should not mutate values', function(assert) {
-      assert.expect(36);
+      assert.expect(38);
 
       function Foo() {}
       Foo.prototype = { 'b': 2 };
@@ -526,6 +526,12 @@
 
       assert.deepEqual(value, deepObject, 'fp.setWith');
       assert.deepEqual(actual, { 'a': { 'b': 2, 'c': 3 }, 'd': { 'e': 4 } }, 'fp.setWith');
+
+      value = _.cloneDeep(deepObject);
+      actual = fp.unset('a.b', value);
+
+      assert.deepEqual(value, deepObject, 'fp.unset');
+      assert.deepEqual(actual, { 'a': { 'c': 3 } }, 'fp.set');
     });
   }());