mdChips: required validator isn't run on model change

[Emeegeemee]

Demo showing required isn't working properly when removing all of the chips.

Expected behavior: ng-message for the required validator should be displayed saying 'At least one chip is required.' It should behave similarly to md-max-chips which can be shown by adding 5 chips.

Current behavior: no message is shown.

[Emeegeemee]

Can you comment on why this feature is deprecated? Is so what is the correct way to handle required with the chips directive.

[ThomasBurleson]

This issue is closed as part of our deprecation effort.
For details, see our post Spring Cleaning 2016.

[vbraun]

The chips model is a list that is mutated in place; It doesn't "change". You need to set up a $watchCollection on the model to track insertion/removal.

[Emeegeemee]

I am aware that the array reference doesn't change. However, your solution to use $watchCollection comes with a performance cost of running every digest cycle that is unnecessary if the validators are run in the mdChips directive per my pull request above. Besides with the addition of the md-max-chips validator, it shows users clearly want validators on the content of the array not the reference to the array.

I don't even need the NgModelController.$isEmpty override just calling the NgModelController.$validate method on content change would allow me to create any validators that I would need.

[hantsy]

There is a md-max-chips, but no md-min-chips, and required is not worked with md-chips.