Using $emit in angular 1.5 component

Question

I am using angular 1.5 component and need to call function in parent controller from when $emit in child component. How we can do this?

Example:

(function (angular) {
    'use strict';

    controllerName.$inject = [];

    function controllerName() {
       var _this = this;
       function toBeCalledOnEmit() {//some code}
       var vm = {
          toBeCalledOnEmit: toBeCalledOnEmit
       }
       angular.extend(_this, vm);
    }

    angular.module('moduleName', [
    ]).component('parentComponenet', {
        templateUrl: 'templateUrl',
        controller: 'controllerName'
    }).controller('controllerName', controllerName);

})(angular);

child component:

(function (angular) {
    'use strict';

    childController.$inject = [];

    function childController() {
       //needs $emit here
    }

    angular.module('childModuleName', [
    ]).component('childComponent', {
        templateUrl: 'templateUrl',
        controller: 'childController'
    }).controller('childController', childController);

})(angular);

Answer 1

I prefer working with a separate event service that exposes subscribe and notify functions. But if you prefer to emit from the child component then it would look like this:

Child Component

    (function (angular) {
    'use strict';

      function childController($scope) {
       $scope.$emit("someEvent", args); 
      }

      angular.module('childModuleName', [
      ]).component('childComponent', {
        templateUrl: 'templateUrl',
        controller: ['$scope', childController]
      });

    })(angular);

Parent Component

    (function (angular) {
    'use strict';


      function controllerName($scope) {
         var _this = this;

         function toBeCalledOnEmit(event, args) {
            //some code
         }
         $scope.on('someEvent', toBeCalledOnEmit);

         var vm = {
            toBeCalledOnEmit: toBeCalledOnEmit
         }
         angular.extend(_this, vm);
      }

      angular.module('moduleName', [
      ]).component('parentComponent', {
          templateUrl: 'templateUrl',
          controller: ['$scope', controllerName]
      });

    })(angular);

Answer 2

Code is attached below:

1. Child Component:

   (function (angular) {
       'use strict';
   
   childController.$inject = ['$scope'];
   
   function childController($scope) {
   
      //needs $emit here
   $scope.$emit("topic-123", 'any message'); 
   }
   
   angular.module('childModuleName', [
   ]).component('childComponent', {
       templateUrl: 'templateUrl',
       controller: 'childController'
   }).controller('childController', childController);
   

   })(angular);

2. Parent Component:

   (function (angular) {
   'use strict';
   
   controllerName.$inject = ['$scope'];
   
   function controllerName($scope) {
      var _this = this;
      function toBeCalledOnEmit() {//some code}
      var vm = {
         toBeCalledOnEmit: toBeCalledOnEmit
      }
   
      $scope.$on('topic-123', function(event, msg) {
     // @TODO  
     toBeCalledOnEmit();
      });
   
      angular.extend(_this, vm);
   }
   
   angular.module('moduleName', [
   ]).component('parentComponenet', {
       templateUrl: 'templateUrl',
       controller: 'controllerName'
   }).controller('controllerName', controllerName);
   

   })(angular);

Answer 3

You can do it like this using $rootScope. It works fine in my case -

child component:

(function (angular) {
 'use strict';

 childController.$inject = ['$rootScope'];

 function childController($rootScope) {
   $rootScope.$emit('myEvent',$scope.data)
 }
})(angular);

Parent Component:

(function (angular) {
 'use strict';

 controllerName.$inject = ['$rootScope'];

 function controllerName($rootScope) {
   var _this = this;
   function toBeCalledOnEmit() {//some code}
   var vm = {
      toBeCalledOnEmit: toBeCalledOnEmit
   }
   $rootScope.$on('myEvent', function(event, msg) {
     toBeCalledOnEmit();
   });
   angular.extend(_this, vm);
 }
})(angular);