Form input directive for Angularjs

forminput.js

(function (module) {

    var watcherFor = function (form, name) {
        return function () {
            if (name && form[name]) {                
                return form[name].$invalid;
            }
        };
    };

    var updaterFor = function (element) {
        return function (hasError) {
            if (hasError) {
                element.removeClass("has-success")
                       .addClass("has-error");
            } else {
                element.addClass("has-success")
                       .removeClass("has-error");
            }
        };
    };

    var setupDom = function (element) {
        var input = element[0].querySelector("input, textarea, select, otf-rating");
        var type = input.getAttribute("type");
        var name = input.getAttribute("name");
        if (type !== "checkbox" && type !== "radio") {
            input.classList.add("form-control");
        }

        var label = element[0].querySelector("label");
        label.classList.add("control-label");
        return name;
    };

    var addMessages = function(form, element, name, $compile, scope) {
        var messages = "<div class='help-block' ng-messages='" +
                        form.$name + "." + name + ".$error" +
                        "' ng-messages-include='templates/messages.html'><div>";
        element.append($compile(messages)(scope));
    };

    var link = function ($compile) {
        return function(scope, element, attributes, form) {
            var name = setupDom(element);
            addMessages(form, element, name, $compile, scope);
            scope.$watch(watcherFor(form, name), updaterFor(element));
        }
    };

    var forminput = function ($compile) {

        return {
            restrict: "A",
            require: "^form",
            link: link($compile)
        };

    };

    module.directive("forminput", forminput);

}(angular.module("forms")));
///
/* messages.html template
<span ng-message="required">This field is required</span>
<span ng-message="min">Too small</span>
<span ng-message="max">Too large</span>
<span ng-message="email">Enter a valid email</span>
<span ng-message="startsWith">Incorrect start</span>
<span ng-message="username">Username is unavailble</span>
*/

/* index.html form example
<form ng-submit="model.submit(profileForm.$valid)" name="profileForm" novalidate>

                <h2>Sign Up Now!</h2>

                <div forminput>
                    <label for="username">Your user name:</label>
                    <input type="text" id="username" name="username" required placeholder="User name"
                           ng-model="model.user.username" username starts-with="S">
                </div>

                <div forminput>
                    <label for="email">Your email:</label>
                    <input type="email" id="email" name="email" required placeholder="Email address" 
                           ng-model="model.user.email">                 
                </div>

                <div forminput>
                    <label for="website">Your website:</label>
                    <input type="url" id="website" name="website" placeholder="Website" 
                           ng-model="model.user.website">
                </div>
*/