Merge pull request jashkenas#2259 from debutt/master

Fixes _.isNaN for wrapped numbers

Author: megawac

test/objects.js

@@ -719,6 +719,7 @@
     ok(!_.isNaN(void 0), 'undefined is not NaN');
     ok(!_.isNaN(null), 'null is not NaN');
     ok(!_.isNaN(0), '0 is not NaN');
+    ok(!_.isNaN(new Number(0)), 'wrapped 0 is not NaN');
     ok(_.isNaN(NaN), 'but NaN is');
     ok(_.isNaN(new Number(NaN)), 'wrapped NaN is still NaN');
   });

underscore.js

@@ -1301,7 +1301,7 @@
 
   // Is the given value `NaN`? (NaN is the only number which does not equal itself).
   _.isNaN = function(obj) {
-    return _.isNumber(obj) && obj !== +obj;
+    return _.isNumber(obj) && isNaN(obj);
   };
 
   // Is a given value a boolean?