Consider a form invalid while async validator promises are pending

Question

I have an async validator:

app.directive('validateBar', ['$http', function($http) {
    function link($scope, $element, $attrs, ngModel) {
        ngModel.$asyncValidators.myValidator = function(value) {
            return $http.get('/endpoint/' + value);
        };
    }
    return {
        require: 'ngModel',
        link: link
    };
}]);

Form template:

<form name="myForm" ng-submit="foo.$valid && saveForm()">
    <input name="bar" ng-model="bar" data-validate-bar>
    <p ng-show="myForm.bar.$error.myValidator">Your bar is wrong</p>
    <button disabled="myForm.$invalid">
</form>

Problem: I want my accompanying form to be invalid while the myValidator promise is pending.

I know two ways to invalidate a form while async validators are pending, but they're both verbose and/or hacky.

// Workaround 1: Mark another validator as invalid while the validator promise is pending.
// I cannot mark 'myValidator' as invalid, gets set to valid immediately by Angular.
app.directive('validateSomething', ['$http', function($http) {
    function link($scope, $element, $attrs, ngModel) {
        ngModel.$setValidity('async', false);
        ngModel.$asyncValidators.myValidator = function(value) {
            return $http.get('/endpoint/' + value).then(function() {
                 ngModel.$setValidity('async', true);
            });
        };
    }
    return {
        require: 'ngModel',
        link: link
    };
}]);

---

<!-- Workaround 2: Prevent submitting through the UI -->
<form name="myForm" ng-submit="myForm.$valid && !myForm.$pending && saveForm()">
    <input name="bar" ng-model="bar" data-validate-bar>
    <p ng-show="myForm.bar.$error.myValidator">Your bar is wrong</p>
    <button disabled="myForm.$invalid || myForm.$pending">
</form>

I don't like workaround 1 because I mark another validator (async) as invalid, which may have unintended side effects, and I don't like workaround 2 because I can no longer trust form.$valid by itself.

Does anyone know a clean solution?

Answer 1

You can use $pending to test if some async validator is pending on the whole form or a specific input element. I also added a test on $pristine to hide error messages when the page loads and used ng-disabled instead of disabled on the button.

<form name="myForm" ng-submit="foo.$valid && saveForm()">
    <input name="bar" ng-model="bar" data-validate-bar>
    <div ng-show="! myForm.$pristine">
      <p ng-show="myForm.bar.$pending.myValidator || myForm.bar.$error.myValidator">Your bar is wrong</p>
    </div>
    <button ng-disabled="myForm.$invalid || myForm.$pending">Do smth</button>
</form>