feat(Change Detection): Child watch groups

modules/change_detection/src/watch_group.js

@@ -50,7 +50,6 @@ export class ProtoWatchGroup {
     if (this.headRecord !== null) {
       this._createRecords(watchGroup, formatters);
       this._setDestination();
-
     }
     return watchGroup;
   }
@@ -88,6 +87,11 @@ export class WatchGroup {
     this.headEnabledRecord = null;
     this.tailEnabledRecord = null;
     this.context = null;
+
+    this.childHead = null;
+    this.childTail = null;
+    this.next = null;
+    this.prev = null;
   }
 
   addRecord(record:Record) {
@@ -149,12 +153,35 @@ export class WatchGroup {
     }
   }
 
-  insertChildGroup(newChild:WatchGroup, insertAfter:WatchGroup) {
-    throw 'not implemented';
+  addChild(child:WatchGroup) {
+    if (isBlank(this.childTail)) {
+      this.childHead = this.childTail = child;
+      this._attachRecordsFromWatchGroup(child);
+
+    } else {
+      this.childTail.next = child;
+      child.prev = this.childTail;
+      this.childTail = child;
+      this._attachRecordsFromWatchGroup(child);
+    }
   }
 
-  remove() {
-    throw 'not implemented';
+  _attachRecordsFromWatchGroup(child:WatchGroup) {
+    if (isPresent(this.tailRecord)) {
+      if (isPresent(child.headRecord)) {
+        this.tailRecord.next = child.headRecord;
+        this.tailRecord.nextEnabled = child.headRecord;
+
+        child.headRecord.prev = this.tailRecord;
+        child.headRecord.prevEnabled = this.tailRecord;
+      }
+    } else {
+      this.headRecord = child.headRecord;
+      this.headEnabledRecord = child.headEnabledRecord;
+    }
+
+    this.tailRecord = child.tailRecord;
+    this.tailEnabledRecord = child.tailEnabledRecord;
   }
 
   /**
@@ -172,6 +199,14 @@ export class WatchGroup {
       record.updateContext(context);
     }
   }
+
+  get _tailRecordIncludingChildren():Record {
+    var lastGroup = this;
+    while (lastGroup.childTail !== null) {
+      lastGroup = lastGroup.childTail;
+    }
+    return lastGroup.tailRecord;
+  }
 }
 
 export class WatchGroupDispatcher {

modules/change_detection/test/watch_group_spec.js

@@ -53,6 +53,92 @@ export function main() {
       });
     });
 
+    describe("adding children", () => {
+      it("should add child watch group", () => {
+        var parent = new WatchGroup(null, null);
+        var child1 = new WatchGroup(null, null);
+        var child2 = new WatchGroup(null, null);
+        parent.addChild(child1);
+        parent.addChild(child2);
+
+        expect(parent.childHead).toBe(child1);
+        expect(parent.childTail).toBe(child2);
+
+        expect(child1.next).toBe(child2);
+        expect(child2.prev).toBe(child1);
+      });
+
+      it("should link all records", () => {
+        var parent = new WatchGroup(null, null);
+        var parentRecord = createRecord(parent);
+        parent.addRecord(parentRecord);
+
+        var child = new WatchGroup(null, null);
+        var childRecord = createRecord(child);
+        child.addRecord(childRecord);
+
+        parent.addChild(child);
+
+        expect(parent.headRecord).toBe(parentRecord);
+        expect(parent.tailRecord).toBe(childRecord);
+
+        expect(parent.headEnabledRecord).toBe(parentRecord);
+        expect(parent.tailEnabledRecord).toBe(childRecord);
+
+        expect(parentRecord.next).toBe(childRecord);
+        expect(childRecord.prev).toBe(parentRecord);
+      });
+
+      it("should work when parent has no records", () => {
+        var parent = new WatchGroup(null, null);
+
+        var child = new WatchGroup(null, null);
+        var childRecord = createRecord(child);
+        child.addRecord(childRecord);
+
+        parent.addChild(child);
+
+        expect(parent.headRecord).toBe(childRecord);
+        expect(parent.tailRecord).toBe(childRecord);
+
+        expect(parent.headEnabledRecord).toBe(childRecord);
+        expect(parent.tailEnabledRecord).toBe(childRecord);
+      });
+
+      it("should work when parent has no records and first child has no records", () => {
+        var parent = new WatchGroup(null, null);
+        var firstChild = new WatchGroup(null, null);
+        parent.addChild(firstChild);
+
+        var child = new WatchGroup(null, null);
+        var childRecord = createRecord(child);
+        child.addRecord(childRecord);
+
+        parent.addChild(child);
+
+        expect(parent.headRecord).toBe(childRecord);
+        expect(parent.tailRecord).toBe(childRecord);
+
+        expect(parent.headEnabledRecord).toBe(childRecord);
+        expect(parent.tailEnabledRecord).toBe(childRecord);
+      });
+
+      it("should work when second child has no records", () => {
+        var parent = new WatchGroup(null, null);
+
+        var firstChild = new WatchGroup(null, null);
+        var childRecord = createRecord(firstChild);
+        firstChild.addRecord(childRecord);
+        parent.addChild(firstChild);
+
+        var secondChild = new WatchGroup(null, null);
+        parent.addChild(secondChild);
+
+        expect(parent.childHead).toBe(firstChild);
+        expect(parent.childTail).toBe(secondChild);
+      });
+    });
+
     describe("enabling/disabling records", () => {
       it("should disable a single record", () => {
         var wg = new WatchGroup(null, null);