track By no longer working

[weisk]

Hi guys,

On v1.3.0-rc.5, track by won't set the inner value on <options> with the desired property. Didn't happen on rc.4.

See plnkr:
http://plnkr.co/edit/sScmKu?p=preview

Reproducable: always
Browsers: independent
Operating system: independent

[jeffbcross]

Hi @weisk are you referring to the fact that the selected attribute isn't being properly updated? If I inspect the value property of the select element I see the correct behavior, but I do see that the selected attributes of options aren't being updated.

[jeffbcross]

But the behavior I mentioned is also present in rc.4, so you must be referring to something else.

[weisk]

See updated plunk:

http://plnkr.co/edit/sScmKu?p=preview

I would expect that track by would allow me to choose which property is used to hold the value of the select, but as you can see in the code, its using the $index property of the repeater, not the id property I wanted.

If you change the angular version to rc4 you will see that it works fine..

[jeffbcross]

Ahh, I see. This was undocumented and untested behavior that was refactored out as we fixed other issues. In your case, since you're not using a select as expression, you could achieve a similar result using ng-repeat, but the model assignment would be the id. Example plunker: http://plnkr.co/edit/2fgiKA?p=preview

[jeffbcross]

There's also been some discussion of making ngValue more powerful to support this use case with ngRepeat, so that you could have value and model be different.

<select ng-model="myModel">
  <option ng-value="item as item.id" ng-repeat="item in items">{{item.name}}</option>
</select>

Where item gets assigned to myModel and the option's value becomes item.id.