JS backend: added dynamic.iterator to simplify the using "iterable" objects.

js/js.libraries/src/core/dynamic.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2010-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlin.js
+
+// TODO add the support ES6 iterators
+public fun dynamic.iterator(): Iterator<dynamic> {
+    val r = this
+
+    return when {
+        this["iterator"] != null ->
+            this["iterator"]()
+        js("Array.isArray(r)") ->
+            (this: Array<*>).iterator()
+
+        else ->
+            (r: Iterable<*>).iterator()
+    }
+}

js/js.tests/test/org/jetbrains/k2js/test/semantics/DynamicTestGenerated.java

@@ -120,6 +120,12 @@ public class DynamicTestGenerated extends AbstractDynamicTest {
         doTest(fileName);
     }
 
+    @TestMetadata("iterator.kt")
+    public void testIterator() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("js/js.translator/testData/dynamic/cases/iterator.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("nameClashing.kt")
     public void testNameClashing() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("js/js.translator/testData/dynamic/cases/nameClashing.kt");

js/js.translator/testData/dynamic/cases/iterator.kt

@@ -0,0 +1,32 @@
+package foo
+
+fun testFor(expected: Int, d: dynamic, case: String) {
+    var actual = 0
+    for (v in d) {
+        actual += v: Int
+    }
+    assertEquals(expected, actual, "testFor on $case")
+}
+
+fun testIterator(expected: Int, d: dynamic, case: String) {
+    var actual = 0
+    val it = d.iterator()
+    while (it.hasNext()) {
+        actual += it.next(): Int
+    }
+    assertEquals(expected, actual, "testIterator on $case")
+}
+
+fun test(expected: Int, d: dynamic, case: String) {
+    testFor(expected, d, case)
+    testIterator(expected, d, case)
+}
+
+fun box(): String {
+    test(6, array(1, 2, 3), "array")
+    test(64, byteArray(42, 22), "byte array")
+    test(66, listOf(55, 3, 8), "list")
+    test(167, setOf(55, 3, 8, 101), "set")
+
+    return "OK"
+}