text: import { ClassDirective } from './class';
  import { directive } from '../../decorator';
  
  @directive({
      namespace: 'sine',
      selector: 'n-class-even'
  })
  class ClassEvenDirective extends ClassDirective {
      constructor() {
          super();
      }
  
      skip() {
          return this.$scope.$index & 1 === 1;
      }
  }