如何使用一个服务来更新AngularJS中的父作用域和子作用域？

app.service('dataService', function($rootScope) {
  var service = {};

  service.parentData = 'Parent Data';
  service.childData = 'Child Data';

  service.updateParentData = function(newData) {
    service.parentData = newData;
    $rootScope.$broadcast('parentDataUpdated');
  };

  service.updateChildData = function(newData) {
    service.childData = newData;
    $rootScope.$broadcast('childDataUpdated');
  };

  return service;
});

app.controller('ParentController', function($scope, dataService) {
  $scope.parentData = dataService.parentData;

  $scope.$on('parentDataUpdated', function() {
    $scope.parentData = dataService.parentData;
  });

  $scope.updateParentData = function(newData) {
    dataService.updateParentData(newData);
  };
});

app.controller('ChildController', function($scope, dataService) {
  $scope.childData = dataService.childData;

  $scope.$on('childDataUpdated', function() {
    $scope.childData = dataService.childData;
  });

  $scope.updateChildData = function(newData) {
    dataService.updateChildData(newData);
  };
});

<div ng-controller="ParentController">
  <h2>Parent Controller</h2>
  <p>Parent Data: {{parentData}}</p>
  <input type="text" ng-model="newParentData">
  <button ng-click="updateParentData(newParentData)">Update Parent Data</button>
</div>

<div ng-controller="ChildController">
  <h2>Child Controller</h2>
  <p>Child Data: {{childData}}</p>
  <input type="text" ng-model="newChildData">
  <button ng-click="updateChildData(newChildData)">Update Child Data</button>
</div>