JSFiddle - React, Tailwind, and code Playground

HTML

<div ng-app="myApp">
    <div ng-controller="editcontroller">
        <ul>
            <li ng-click="menuclick()" ng-class="activemenufirst">test</li>
            <li ng-click="menuclick()" ng-class="testclass">test</li>
            <li ng-click="menuclick()" ng-class="testclass">test</li>
            <li ng-click="menuclick()" ng-class="testclass">test</li>
        </ul>
    </div>
</div>

CSS

.active{
    color: red;
}

JavaScript

angular.module('myApp', [
])
    .controller('editcontroller', function ($scope) {
    $scope.activemenufirst = 'red';
    $scope.menuclick = function menuclick() {
        event.preventDefault();
        $scope.activemenufirst = ' ';
        alert('test');

    };

});