JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.angularjs.org/angular-1.0.0rc8.js"></script>
<div ng-controller="MyController">
    <h1>{{test}}</h1>
    <hr />
    <input type="text" my-directive="test" />
</div>

JavaScript

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

myApp.directive('myDirective', function () {
    var linker = function (scope, element, attrs) {
        attrs.$set('ng-model', attrs.myDirective);
        attrs.$set('ng-class', '{\'class\' : testFunction()}');
    }
    return {
        restrict: 'A',        
        link: linker
    }
});

function MyController($scope) {
     $scope.test = 'test';  
    
    $scope.testFunction = function () {
       return true;   
    };
}