From 2884f8acb8e7380c5c77d3522aaa4373c1f674f2 Mon Sep 17 00:00:00 2001
From: jdalton <john.david.dalton@gmail.com>
Date: Thu, 26 Mar 2015 13:17:41 -0700
Subject: [PATCH] Ensure `_.intersection` of a single array returns an empty
 array. [closes #1085]

---
 lodash.src.js |  7 +++++--
 test/test.js  | 16 ++++++++--------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/lodash.src.js b/lodash.src.js
index d14db3568..f18c1fa8f 100644
--- a/lodash.src.js
+++ b/lodash.src.js
@@ -5094,7 +5094,8 @@
           argsLength = arguments.length,
           caches = [],
           indexOf = getIndexOf(),
-          isCommon = indexOf == baseIndexOf;
+          isCommon = indexOf == baseIndexOf,
+          result = [];
 
       while (++argsIndex < argsLength) {
         var value = arguments[argsIndex];
@@ -5104,10 +5105,12 @@
         }
       }
       argsLength = args.length;
+      if (argsLength < 2) {
+        return result;
+      }
       var array = args[0],
           index = -1,
           length = array ? array.length : 0,
-          result = [],
           seen = caches[0];
 
       outer:
diff --git a/test/test.js b/test/test.js
index 92c2a93ad..d71befd8b 100644
--- a/test/test.js
+++ b/test/test.js
@@ -6595,14 +6595,14 @@
       deepEqual(actual, [1, 2]);
     });
 
-    test('should return an array of unique values', 2, function() {
-      var array = [1, 1, 3, 2, 2];
-      deepEqual(_.intersection(array, [5, 2, 2, 1, 4], [2, 1, 1]), [1, 2]);
-      deepEqual(_.intersection(array), [1, 3, 2]);
+    test('should return an array of unique values', 1, function() {
+      var actual = _.intersection([1, 1, 3, 2, 2], [5, 2, 2, 1, 4], [2, 1, 1]);
+      deepEqual(actual, [1, 2]);
     });
 
     test('should match `NaN`', 1, function() {
-      deepEqual(_.intersection([1, NaN, 3], [NaN, 5, NaN]), [NaN]);
+      var actual = _.intersection([1, NaN, 3], [NaN, 5, NaN]);
+      deepEqual(actual, [NaN]);
     });
 
     test('should work with large arrays of objects', 1, function() {
@@ -6627,7 +6627,7 @@
 
     test('should ignore values that are not arrays or `arguments` objects', 3, function() {
       var array = [0, 1, null, 3];
-      deepEqual(_.intersection(array, 3, null, { '0': 1 }), array);
+      deepEqual(_.intersection(array, 3, null, { '0': 1 }), []);
       deepEqual(_.intersection(null, array, null, [2, 1]), [1]);
       deepEqual(_.intersection(array, null, args, null), [1, 3]);
     });
@@ -16405,7 +16405,7 @@
       }
 
       deepEqual(_.difference(null, array), [], message('difference'));
-      deepEqual(_.intersection(null, array), array, message('intersection'));
+      deepEqual(_.intersection(null, array), [], message('intersection'));
       deepEqual(_.union(null, array), array, message('union'));
       deepEqual(_.xor(null, array), array, message('xor'));
     });
@@ -16416,7 +16416,7 @@
       }
 
       deepEqual(_.difference(array, null), array, message('difference'));
-      deepEqual(_.intersection(array, null), array, message('intersection'));
+      deepEqual(_.intersection(array, null), [], message('intersection'));
       deepEqual(_.union(array, null), array, message('union'));
     });
   }(1, null, [3], null, 5));