fix(change_detection): expose values when detecting changes in key-value pairs

Fixes angular#1118 Closes angular#1123

Author: pkozlowski-opensource

modules/angular2/src/change_detection/pipes/keyvalue_changes.js

@@ -107,9 +107,9 @@ export class KeyValueChanges extends Pipe {
  var newSeqRecord;
  if (oldSeqRecord !== null && key === oldSeqRecord.key) {
  newSeqRecord = oldSeqRecord;
- if (!looseIdentical(value, oldSeqRecord._currentValue)) {
- oldSeqRecord._previousValue = oldSeqRecord._currentValue;
- oldSeqRecord._currentValue = value;
+ if (!looseIdentical(value, oldSeqRecord.currentValue)) {
+ oldSeqRecord.previousValue = oldSeqRecord.currentValue;
+ oldSeqRecord.currentValue = value;
  this._addToChanges(oldSeqRecord);
  }
  } else {
@@ -124,7 +124,7 @@ export class KeyValueChanges extends Pipe {
  } else {
  newSeqRecord = new KVChangeRecord(key);
  MapWrapper.set(records, key, newSeqRecord);
- newSeqRecord._currentValue = value;
+ newSeqRecord.currentValue = value;
  this._addToAdditions(newSeqRecord);
  }
  }
@@ -158,11 +158,11 @@ export class KeyValueChanges extends Pipe {
  }
 
  for (record = this._changesHead; record !== null; record = record._nextChanged) {
- record._previousValue = record._currentValue;
+ record.previousValue = record.currentValue;
  }
 
  for (record = this._additionsHead; record != null; record = record._nextAdded) {
- record._previousValue = record._currentValue;
+ record.previousValue = record.currentValue;
  }
 
  // todo(vicb) once assert is supported
@@ -215,8 +215,8 @@ export class KeyValueChanges extends Pipe {
  }
 
  for (var rec:KVChangeRecord = this._removalsHead; rec !== null; rec = rec._nextRemoved) {
- rec._previousValue = rec._currentValue;
- rec._currentValue = null;
+ rec.previousValue = rec.currentValue;
+ rec.currentValue = null;
  MapWrapper.delete(this._records, rec.key);
  }
  }
@@ -351,8 +351,8 @@ export class KeyValueChanges extends Pipe {
 
 export class KVChangeRecord {
  key;
- _previousValue;
- _currentValue;
+ previousValue;
+ currentValue;
 
  _nextPrevious:KVChangeRecord;
  _next:KVChangeRecord;
@@ -363,8 +363,8 @@ export class KVChangeRecord {
 
  constructor(key) {
  this.key = key;
- this._previousValue = null;
- this._currentValue = null;
+ this.previousValue = null;
+ this.currentValue = null;
 
  this._nextPrevious = null;
  this._next = null;
@@ -375,9 +375,9 @@ export class KVChangeRecord {
  }
 
  toString():string {
- return looseIdentical(this._previousValue, this._currentValue) ?
+ return looseIdentical(this.previousValue, this.currentValue) ?
  stringify(this.key) :
- (stringify(this.key) + '[' + stringify(this._previousValue) + '->' +
- stringify(this._currentValue) + ']');
+ (stringify(this.key) + '[' + stringify(this.previousValue) + '->' +
+ stringify(this.currentValue) + ']');
  }
 }

modules/angular2/test/change_detection/keyvalue_changes_spec.js

@@ -54,6 +54,24 @@ export function main() {
  }));
  });
 
+ it('should expose previous and current value', () => {
+ var previous, current;
+
+ MapWrapper.set(m, 1, 10);
+ changes.check(m);
+
+ MapWrapper.set(m, 1, 20);
+ changes.check(m);
+
+ changes.forEachChangedItem((record) => {
+ previous = record.previousValue;
+ current = record.currentValue;
+ })
+
+ expect(previous).toEqual(10);
+ expect(current).toEqual(20);
+ });
+
  it('should do basic map watching', () => {
  changes.check(m);