Add constructors for JSArray

tests/corelib/iterable_to_list_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 
+dynamicCheck(input, {isInt, isString}) {
+  var copy = input.toList();
+  Expect.isTrue(isInt == copy is List<int>);
+  Expect.isTrue(isString == copy is List<String>);
+}
+
 main() {
   List<int> list1 = <int>[1, 2, 3];
   List<int> list2 = const <int>[4, 5];
   List<String> list3 = <String>[];
   Set<int> set1 = new Set<int>();
   set1..add(11)
       ..add(12)
       ..add(13);
   Set<String> set2 = new Set<String>();
   set2..add("foo")
       ..add("bar")
       ..add("toto");
   Set set3 = new Set();
 
   var listCopy = list1.toList();
   Expect.listEquals(list1, listCopy);
   Expect.isTrue(listCopy is List<int>);
   Expect.isFalse(listCopy is List<String>);
   Expect.isFalse(identical(list1, listCopy));
+  dynamicCheck(list1, isInt: true, isString: false);
 
   listCopy = list2.toList();
   Expect.listEquals(list2, listCopy);
   Expect.isTrue(listCopy is List<int>);
   Expect.isFalse(listCopy is List<String>);
   Expect.isFalse(identical(list2, listCopy));
+  dynamicCheck(list2, isInt: true, isString: false);
 
   listCopy = list3.toList();
   Expect.listEquals(list3, listCopy);
   Expect.isTrue(listCopy is List<String>);
   Expect.isFalse(listCopy is List<int>);
   Expect.isFalse(identical(list3, listCopy));
+  dynamicCheck(list3, isInt: false, isString: true);
 
   listCopy = set1.toList();
   Expect.equals(3, listCopy.length);
   Expect.isTrue(listCopy.contains(11));
   Expect.isTrue(listCopy.contains(12));
   Expect.isTrue(listCopy.contains(13));
   Expect.isTrue(listCopy is List<int>);
   Expect.isFalse(listCopy is List<String>);
+  dynamicCheck(set1, isInt: true, isString: false);
 
   listCopy = set2.toList();
   Expect.equals(3, listCopy.length);
   Expect.isTrue(listCopy.contains("foo"));
   Expect.isTrue(listCopy.contains("bar"));
   Expect.isTrue(listCopy.contains("toto"));
   Expect.isTrue(listCopy is List<String>);
   Expect.isFalse(listCopy is List<int>);
+  dynamicCheck(set2, isInt: false, isString: true);
 
   listCopy = set3.toList();
   Expect.isTrue(listCopy.isEmpty);
   Expect.isTrue(listCopy is List<int>);
   Expect.isTrue(listCopy is List<String>);
+  dynamicCheck(set3, isInt: true, isString: true);
 }