为什么从未调用angularjs链接函数？

Question

永远不会调用Angularjs链接函数。

源代码包含在webpack包中。

角度版本是v1.6.6

import angular from 'angular';

const module = angular.module('app.directives.ax', []);

console.log('included directive');
module.directive('ax', function() {
  return {
    restrict: 'AEC',
    link: function(scope, elem, attrs) {
      console.log('from directive');
      console.log('from directive xxx');
      elem.css('cursor', 'pointer');
      if (attrs.ngClick || attrs.href === '' || attrs.href === '#') {
        elem.on('click', function(e){
          e.preventDefault();
        });
      }
    }
 };
});

export default module.name;

在html模板中我有

<a class="default-link ax" ng-click="vm.delete(announcement.id)"><i class="fa fa-trash-o"></i></a>