fix(record-range): fixes bug when disabling empty ranges.

Author: rkirov

modules/change_detection/src/record_range.js

@@ -188,8 +188,11 @@ export class RecordRange {
  var firstEnabledChildRecord = this.findFirstEnabledRecord();
  var lastEnabledChildRecord = this.findLastEnabledRecord();
 
- var nextEnabled = lastEnabledChildRecord.nextEnabled;
- var prevEnabled = firstEnabledChildRecord.prevEnabled;
+ var nextEnabled = isPresent(lastEnabledChildRecord) ?
+ lastEnabledChildRecord.nextEnabled : null;
+
+ var prevEnabled = isPresent(firstEnabledChildRecord) ?
+ firstEnabledChildRecord.prevEnabled : null;
 
  if (isPresent(nextEnabled)) nextEnabled.prevEnabled = prevEnabled;
  if (isPresent(prevEnabled)) prevEnabled.nextEnabled = nextEnabled;

modules/change_detection/test/record_range_spec.js

@@ -107,6 +107,14 @@ export function main() {
  expect(enabledRecords(parent, recordNames)).toEqual(['record1', 'record2']);
  });
 
+ it('should handle enabling/disabling an empty range', () => {
+ var emptyRange = new RecordRange(null, null);
+ emptyRange.disable();
+ emptyRange.enable();
+
+ expect(enabledRecords(emptyRange, recordNames)).toEqual([]);
+ });
+
  it('should handle adding a range into an empty range', () => {
  var emptyRange = new RecordRange(null, null);
  parent.addRange(emptyRange);