docs(ngModel): $setViewValue does not check validity before updating model

[niallsmart]

Removes an incorrect assertion in the docs for $setViewValue. It actually updates the model regardless of the control validity.

[mary-poppins]

Thanks for the PR!

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Thanks again for your help!

[IgorMinar]

thanks but this change wasn't quite correct either. I clarified the docs in a separate commit.

thanks again.

[niallsmart]

@IgorMinar Good call on the longer comment. However I think the sentence "if validators determine the value is invalid, the $modelValue and the model path will be set to undefined" is a bit misleading. Unless I'm misunderstanding the code, $setViewValue will use whatever value is returned by this.$parsers, regardless of whether they mark the value as invalid.

So, if you implement a custom validator, then just setting the control validity is not enough, you must also return undefined – $setViewValue will not do that for you.

[petebacondarwin]

@niallsmart - I agree that the model will be set to whatever the value is returned by the last $parser in the pipeline. As it turns out, all the built-in validation directives "do" set this return to undefined if they are invalid. @IgorMinar - We should update the docs, again.

[niallsmart]

@petebacondarwin the pull request linked to above clarifies this I think, which Igor merged earlier today.

[rinatio]

Hey guys!

I'm a little bit confused, what is an idea behind setting $modelValue to the undefined if validation fails? In case we have a watcher for this value in a controller and ngModel becomes invalid and then back valid with the same value the watcher will be triggered again and again. Here's an example to illustrate my question. Please advise how to handle such cases?

[petebacondarwin]

@rinatio - The idea is that the model should only contain valid values or undefined. If you make the $viewValue invalid then the validation/parsers will pass undefined to the model. This is a convention. It would be possible to not change the model if the view becomes invalid but then you would have the potential for confusion and inconsistency between the view and the model. At least this way you can choose not to react if the model becomes undefined or to store your own copy of the valid model:

$scope.$watch('model', function(newVal, oldVal) {
  if ( newVal !== undefined ) {
    $scope.validModel = newVal;
  }
});

Then if you watch this validModel property it will only change when the model goes from one valid value to another.

[rinatio]

@petebacondarwin thanks, it makes sense. Maybe it is possible to ask explicitly ngModelController to use only last valid value? Like having some additional option in ng-model-options?

[petebacondarwin]

I would be interested to see your use-case, as in general people have not had this issue before.

[rinatio]

@petebacondarwin it is pretty simple. Every time input's value got changed, we send a new ajax request. In case ngModel becomes invalid and then back valid with same value (as in example) the request is being sent again. Setting ng-model-options="{ updateOn: 'blur'}" will probably help me in my case, although there might be other use-cases. Anyway, just wondering