fix(cd): report all changes on first cd run

- null values would not have been reported for Dart
- undefined values would not have been reported for JS

Closes angular#454

Author: vicb

modules/change_detection/src/dynamic_change_detector.js

@@ -21,6 +21,8 @@ import {
 import {ChangeDetector, ChangeRecord, ChangeDispatcher} from './interfaces';
 import {ExpressionChangedAfterItHasBeenChecked, ChangeDetectionError} from './exceptions';
 
+var _uninitialized = new Object();
+
 class SimpleChange {
   previousValue:any;
   currentValue:any;
@@ -43,6 +45,7 @@ export class DynamicChangeDetector extends ChangeDetector {
     this.dispatcher = dispatcher;
     this.formatters = formatters;
     this.values = ListWrapper.createFixedSize(protoRecords.length + 1);
+    ListWrapper.fill(this.values, _uninitialized);
     this.protos = protoRecords;
 
     this.children = [];
@@ -123,10 +126,9 @@ export class DynamicChangeDetector extends ChangeDetector {
     var prevValue = this._readSelf(proto);
     var currValue = this._calculateCurrValue(proto);
 
-    if (! isSame(prevValue, currValue)) {
+    if (!isSame(prevValue, currValue)) {
       this._writeSelf(proto, currValue);
-      return new SimpleChange(prevValue, currValue);
-
+      return new SimpleChange(prevValue === _uninitialized ? null : prevValue, currValue);
     } else {
       return null;
     }
@@ -174,7 +176,7 @@ export class DynamicChangeDetector extends ChangeDetector {
     var self = this._readSelf(proto);
     var context = this._readContext(proto);
 
-    if (isBlank(self)) {
+    if (isBlank(self) || self === _uninitialized) {
       if (ArrayChanges.supports(context)) {
         self = new ArrayChanges();
       } else if (KeyValueChanges.supports(context)) {

modules/change_detection/test/change_detection_spec.js

@@ -57,6 +57,16 @@ export function main() {
       expect(dispatcher.log).toEqual(['name=Misko']);
     });
 
+    it('should report all changes on the first run including uninitialized values', () => {
+      var uninit = new Uninitialized();
+      var c = createChangeDetector('value', 'value', uninit);
+      var cd = c["changeDetector"];
+      var dispatcher = c["dispatcher"];
+
+      cd.detectChanges();
+      expect(dispatcher.log).toEqual(['value=null']);
+    });
+
     it("should support literals", () => {
       expect(executeWatch('const', '10')).toEqual(['const=10']);
       expect(executeWatch('const', '"str"')).toEqual(['const=str']);
@@ -237,10 +247,10 @@ export function main() {
         pcd.addAst(ast('invalidProp', 'someComponent'), "a", 1);
 
         var cd = pcd.instantiate(new TestDispatcher(), null);
+        cd.setContext(null);
 
         try {
           cd.detectChanges();
-
           throw new BaseException("fail");
         } catch (e) {
           expect(e).toBeAnInstanceOf(ChangeDetectionError);
@@ -430,6 +440,10 @@ class Address {
   }
 }
 
+class Uninitialized {
+  value:any;
+}
+
 class TestData {
   a;
 
@@ -474,4 +488,4 @@ class TestDispatcher extends ChangeDispatcher {
   _asString(value) {
     return (isBlank(value) ? 'null' : value.toString());
   }
-}
+}

modules/facade/src/collection.dart

@@ -2,6 +2,7 @@ library facade.collection;
 
 import 'dart:collection' show HashMap, IterableBase, Iterator;
 export 'dart:core' show Map, List, Set;
+import 'dart:math' show max, min;
 
 class MapIterator extends Iterator<List> {
   Iterator _iterator;
@@ -105,6 +106,18 @@ class ListWrapper {
   static void clear(List l) { l.clear(); }
   static String join(List l, String s) => l.join(s);
   static bool isEmpty(list) => list.isEmpty;
+  static void fill(List l, value, [int start = 0, int end]) {
+    // JS semantics
+    // see https://github.com/google/traceur-compiler/blob/81880cd3f17bac7de90a4cd0339e9f1a9f61d24c/src/runtime/polyfills/Array.js#L94
+    int len = l.length;
+    start = start < 0 ? max(len + start, 0) : min(start, len);
+    if (end == null) {
+      end = len;
+    } else {
+      end = end < 0 ? max(len + end, 0) : min(end, len);
+    }
+    l.fillRange(start, end, value);
+  }
 }
 
 bool isListLikeIterable(obj) => obj is Iterable;

modules/facade/src/collection.es6

@@ -166,6 +166,9 @@ export class ListWrapper {
   static isEmpty(list) {
     return list.length == 0;
   }
+  static fill(list:List, value, start:int = 0, end:int = undefined) {
+    list.fill(value, start, end);
+  }
 }
 
 export function isListLikeIterable(obj):boolean {