AngularJS: Is there any way to determine which fields are making a form invalid?

Each input name‘s validation information is exposed as property in form‘s name in scope.

HTML

<form name="someForm" action="https://stackoverflow.com/">
    <input name="username" required />
    <input name="password" type="password" required />
</form>

JS

$scope.someForm.username.$valid
// > false
$scope.someForm.password.$error
// > { required: true }

The exposed properties are $pristine, $dirty, $valid, $invalid, $error.

If you want to iterate over the errors for some reason:

$scope.someForm.$error
// > { required: [{$name: "username", $error: true /*...*/},
//                {$name: "password", /*..*/}] }

Each rule in error will be exposed in $error.

Here is a plunkr to play with http://plnkr.co/edit/zCircDauLfeMcMUSnYaO?p=preview