Angular 1.3.x Directive to fetch minlength Value from Input Text Field and show the Value in the ng-message for minlength Errors

errors_tpl.html

<small class="error" ng-message="minlength" validate-minlength>Please enter at least {{requiredMinLength}} characters</small>

form.html

<form name="userRegForm">

    <fieldset>

        <legend>User Registration</legend>

        <label>
            Username
            <input type="text"
                    ng-model="user.username"
                    name="user"
                    minlength="4"
                    required
            >
            <div role="alert"
                ng-show="userRegForm.user.$invalid && userRegForm.user.$dirty"
                ng-messages="userRegForm.user.$error"
                ng-messages-include="errors_tpl.html"
            ></div>

        </label>

        <button type="submit" class="button postfix">Save</button>

    </fieldset>

</form>

minlengthDir.js

(function ( ) {

    'use strict';

    var app = angluar.module('flyweb');

    app.directive('validateMinlength', validateMinlength);

    app.directive('minlength', minlength);

    function validateMinlength(  ) {

        return {

            restrict : 'A',
            require  : '^form',
            link     : linkFunction

        };

        function linkFunction( scope, element, attrs, ctrl ) {

            scope.$watch( error, errorMsg );

            function error( ) {

                return ctrl.$error.minlength;

            }

            function errorMsg( ) {

                if ( ctrl.$error.minlength ){

                    scope.requiredMinLength = ctrl.$error.minlength[0].$minlength;

                }

            }

        }

    }


    function minlength(  ) {

        return {

            restrict    : 'A',
            require     : '^ngModel',
            link        : function ( scope, element, attrs, ngModelCtrl ) {

                            ngModelCtrl.$minlength = attrs.minlength;

                        }

        };

    }


}( ));