title: Pass array in directive attributes
body: <p>I want to pass array in the directive attribute. It doesn't work. I tried to pass an array in the attribute of a directive and nothing happened.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>class Directive {
    constructor () {
      'ngInject';
  
      let directive = {
        restrict: 'E',
        template: '&lt;div class="btn-group"&gt;
                     &lt;label class="btn btn-primary classButton" 
                            ng-model="radioModel" uib-btn-radio="'First'" 
                            config="{{config[0]}}"&gt;{{config[0]}}
                     &lt;/label&gt;
                   &lt;/div&gt;',
  
        controller: Controller,
        controllerAs: 'vm',
        bindToController: true,
        scope: {
          config: '='
        }
      };
  
      return directive;
    }
  }
  
  class Controller {
    constructor() {
      'ngInject';
    }
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;directive config="First, Second"&gt;&lt;/directive&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p><strong>How should I pass the array to the directive?</strong></p>