AngularJS Toggle Buttons

HTML

<button ng-click="toggle()">test </button>
<div ng-class="{{state}}" >
    hello test
</div>

CSS

.vis{
    
     height:100px;
     display:none;
}

JavaScript

function ctrl($scope) {    
    $scope.state = vis;
    $scope.toggle = function () {
      state = !state;
    };
}