JSFiddle - React, Tailwind, and code Playground

HTML

<body ng-app="myApp">

<div>
    <form name="myForm">
        Name: <input name="name" type="text" ng-model="name" name-validation="" my-minlength="3"  my-maxlength="16" my-pattern="/^\w+$/"/>
        <div ng-show="myForm.name.$dirty && myForm.name.$invalid">
            <span ng-show="myForm.name.$error.pattern">Pattern error</span>
            <span ng-show="myForm.name.$error.length">Length error</span>
        </div>
        <br/>
        <input type="submit" value="Submit">
    </form>
</div>
</body>

JavaScript

var mod = angular.module("myApp", []);

mod.directive("nameValidation", function () {
    return {
        restrict: "A",
        require: "ngModel",
        link: function (scope, element, attrs, ngModelCtrl) {
            var validate = function (value) {
                var minLen = parseInt(attrs.myMinlength, 10),
                    maxLen = parseInt(attrs.myMaxlength, 10),
                    pattern = attrs.myPattern,
                    match = pattern.match(/^\/(.*)\/([gim]*)$/),
                    lenErr = false;
                
                if (match) {
                    pattern = new RegExp(match[1], match[2]);   
                }
                if (!ngModelCtrl.$isEmpty(value)) {
                    ngModelCtrl.$setValidity("pattern", true);
                    if ((minLen && value.length < minLen) || (maxLen && value.length > maxLen)) {
                        ngModelCtrl.$setValidity("length", false);
                        lenErr = true;
                    }
                    else {
                        ngModelCtrl.$setValidity("length", true);
                        lenErr = false;
                    }
                
                    if (!lenErr) {
                        if (match && !pattern.test(value)) {
                            ngModelCtrl.$setValidity("pattern", false);
                        }
                        else {
                            ngModelCtrl.$setValidity("pattern", true);
                        }
                    }
                }
                else {
                    ngModelCtrl.$setValidity("length", true);
                    ngModelCtrl.$setValidity("pattern", true);
                }
            }
        
            ngModelCtrl.$parsers.push(validate);
            ngModelCtrl.$formatters.push(validate);
        }
    }
});