From efb1f4c577c4ae2dfcdd79a4605831045f1e3156 Mon Sep 17 00:00:00 2001
From: Matt Chapman <Matt@NinjitsuWeb.com>
Date: Mon, 22 Jul 2013 18:37:04 -0700
Subject: [PATCH] improve consistency in existence functions

---
 underscore.util.existential.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/underscore.util.existential.js b/underscore.util.existential.js
index 9fd72fe..64ffd62 100644
--- a/underscore.util.existential.js
+++ b/underscore.util.existential.js
@@ -13,19 +13,20 @@
   // Helpers
   // -------
 
-  
+
   // Mixing in the truthiness
   // ------------------------
 
   _.mixin({
-    exists: function(x) { return x != null; },
+    exists: function(x) { return typeof x !== "undefined" && x !== null; },
     truthy: function(x) { return (x !== false) && _.exists(x); },
     falsey: function(x) { return !_.truthy(x); },
     not:    function(b) { return !b; },
     firstExisting: function() {
         for (var i = 0; i < arguments.length; i++) {
-            if (arguments[i] != null) return arguments[i];
+            if (_.exists(arguments[i])) return arguments[i];
         }
+        return undefined;
     }
   });