JSFiddle - React, Tailwind, and code Playground

HTML

<div ng-app="" ng-controller="validateCtrl" name="myForm" novalidate ng-form>
  <p>Username:<br>
      <input type="text" name="user" ng-model="user" required/>
     <span style="color:red" ng-show="myForm.user.$dirty && myForm.user.$invalid">
         <span ng-show="myForm.user.$error.required">Username is required.</span>
      </span>
 </p>

</div>

JavaScript

function validateCtrl($scope){
}