isArray() and isArrayLike() fixes:

* lang.isArrayLike should return bool for falsey arguments
* correct isArray for falsey values, cross frames and array extensions

Fixes #18251.

_base/lang.js

@@ -256,13 +256,12 @@ define(["./kernel", "../has", "../sniff"], function(dojo, has){
 			return (typeof it == "string" || it instanceof String); // Boolean
 		},
 
-		isArray: function(it){
+		isArray: Array.isArray || function(it){
 			// summary:
 			//		Return true if it is an Array.
-			//		Does not work on Arrays created in other windows.
 			// it: anything
 			//		Item to test.
-			return it && (it instanceof Array || typeof it == "array"); // Boolean
+			return opts.call(it) == "[object Array]"; // Boolean
 		},
 
 		isFunction: function(it){
@@ -296,7 +295,7 @@ define(["./kernel", "../has", "../sniff"], function(dojo, has){
 			//		and DOM collections will return true when passed to
 			//		isArrayLike(), but will return false when passed to
 			//		isArray().
-			return it && it !== undefined && // Boolean
+			return !!it && // Boolean
 				// keep out built-in constructors (Number, String, ...) which have length
 				// properties
 				!lang.isString(it) && !lang.isFunction(it) &&
@@ -613,4 +612,3 @@ define(["./kernel", "../has", "../sniff"], function(dojo, has){
 
 	return lang;
 });
-

tests/_base/lang.js

@@ -111,13 +111,40 @@ define(["doh/main", "dojo/_base/array", "dojo/_base/lang", "dojo/_base/kernel"
 			t.assertTrue(lang.isArray([]));
 			t.assertTrue(lang.isArray(new Array()));
 			t.assertFalse(lang.isArray({}));
+			t.assertFalse(lang.isArray(''));
+			t.assertFalse(lang.isArray(0));
+			t.assertFalse(lang.isArray(NaN));
+			t.assertFalse(lang.isArray(null));
+			t.assertFalse(lang.isArray(undefined));
+			if(typeof window != "undefined"){
+				t.assertFalse(lang.isArray(window));
+			}
+			t.assertFalse(lang.isArray(Function));
+
+			function Tricky() {}
+			Tricky.prototype = [];
+			t.assertFalse(lang.isArray(new Tricky));
 		},
 
 		function isArrayLike(t){
 			t.assertFalse(lang.isArrayLike("thinger"));
 			t.assertTrue(lang.isArrayLike(new Array()));
 			t.assertFalse(lang.isArrayLike({}));
 			t.assertTrue(lang.isArrayLike(arguments));
+			t.assertFalse(lang.isArrayLike(""));
+			t.assertFalse(lang.isArrayLike(false));
+			t.assertFalse(lang.isArrayLike(NaN));
+			t.assertFalse(lang.isArrayLike(undefined));
+			t.assertFalse(lang.isArrayLike(null));
+			if(typeof window != "undefined"){
+				t.assertTrue(lang.isArrayLike(window));
+			}
+			t.assertFalse(lang.isArrayLike(Function));
+
+			t.assertTrue(lang.isArrayLike({0: 1, 1: 2, length: 2}));
+			function Tricky() {}
+			Tricky.prototype = [];
+			t.assertTrue(lang.isArrayLike(new Tricky));
 		},
 
 		function isString(t){