Fixing isArrayLike to allow length as a param. Added test

lib/utils.js

@@ -130,6 +130,16 @@ function trim(str) {
   return str.replace(/^\s*/, '').replace(/\s*$/, '');
 }
 
+/**
+ * Determine if a value is an Arguments object
+ *
+ * @param {Object} val The value to test
+ * @returns {boolean} True if value is an Arguments object, otherwise false
+ */
+function isArguments(val) {
+  return toString.call(val) === '[object Arguments]';
+}
+
 /**
  * Iterate over an Array or an Object invoking a function for each item.
  *
@@ -149,7 +159,7 @@ function forEach(obj, fn) {
   }
 
   // Check if obj is array-like
-  var isArrayLike = isArray(obj) || (typeof obj === 'object' && !isNaN(obj.length));
+  var isArrayLike = isArray(obj) || isArguments(obj);
 
   // Force an array if not already something iterable
   if (typeof obj !== 'object' && !isArrayLike) {