Form Validation - Email Validation not working as expected in AngularJs

Question 1

Refer to my another answer: AngularJS v1.3.x Email Validation Issue

Try to use ng-pattern in your email input.

<input type="email" name="input" ng-model="text" ng-pattern="/^[_a-z0-9]+(\.[_a-z0-9]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,4})$/" required>

It fits your valid and invalid cases.

See an example: plunk

Question 2

These emails are valid, as they can be local emails or to an intranet email server: Domains.

The TLD is not required for local emails. As shown in the Wikipedia example, the domain may even contain an IP Address in place of the domain.

Question 3

Even better, now, Angular has email validator built-in, from Angular 4 onwards https://github.com/angular/angular/blob/master/CHANGELOG.md#features-6 https://github.com/angular/angular/pull/13709

Just add email to the tag. For example

  <form #f="ngForm">
    <input type="email" ngModel name="email" required email>
    <button [disabled]="!f.valid">Submit</button>
    <p>Form State: {{f.valid?'VALID':'INVALID'}}</p>
  </form>

Question 4

As ReCaptcha suggested I ended up creating a custom validation directive

var app = angular.module('login-form', []);
var INTEGER_REGEXP = new RegExp('^[a-z0-9]+(\.[_a-z0-9]+)*@@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,50})$', 'i');
app.directive('cemail', function () {
    return {
        require: 'ngModel',
        link: function (scope, elm, attrs, ctrl) {
            ctrl.$parsers.unshift(function (viewValue) {
                if (INTEGER_REGEXP.test(viewValue)) {
                    // it is valid
                    ctrl.$setValidity('cemail', true);
                    return viewValue;
                } else {
                    // it is invalid, return undefined (no model update)
                    ctrl.$setValidity('cemail', false);
                    return undefined;
                }
            });
        }
    };
});

and in html

<label>Email</label>
<input id="UserName" name="UserName" type="text" value="" data-ng-model="email" required="" cemail>
<span data-ng-show="form.UserName.$dirty && form.UserName.$invalid">
    <span data-ng-show="form.UserName.$error.required">Required</span>
    <span data-ng-show="form.UserName.$error.cemail">Invalid Email</span>
</span>

Question 5

I have written a directive that uses the same email validation regular expression that ASP.Net uses. While this may not cover 100% of scenarios, it will cover the vast majority and works perfectly for what we need to cover.

function email() {
return {
    restrict: 'A',
    require: 'ngModel',
    link: function (scope, elem, attrs, ctrl) {
        if (!ctrl) {
            return false;
        }

        function isValidEmail(value) {
            if (!value) {
                return false;
            }
            // Email Regex used by ASP.Net MVC
            var regex = /^[\w-]+(\.[\w-]+)*@([a-z0-9-]+(\.[a-z0-9-]+)*?\.[a-z]{2,6}|(\d{1,3}\.){3}\d{1,3})(:\d{4})?$/i;
            return regex.exec(value) != null;
        }

        scope.$watch(ctrl, function () {
            ctrl.$validate();
        });

        ctrl.$validators.email = function (modelValue, viewValue) {
            return isValidEmail(viewValue);
        };
    }
};
}

Use it like this:

<input type="email" ng-model="$scope.emailAddress" name="newEmailAddress" email/>

Question 6

Angular 6

I generally don't want to allow $$$@$$$ format and always expect a TLD (like .com, .net, .org, etc).

In addition to angular email validator I add my regex pattern to make it work.

 <input type="email" name="email" pattern="^\S*[@]\S*[.]\S*$" email required />

pattern="^\S*[@]\S*[.]\S*$" will make sure that there is a @ and a . followed by a string. This will be an addition to Angular's email validation.