diff --git a/frontend/app/components/wp-relations/child-relations-handler/child-relations-handler.service.ts b/frontend/app/components/wp-relations/child-relations-handler/child-relations-handler.service.ts
new file mode 100644
index 0000000000..59e5a86f98
--- /dev/null
+++ b/frontend/app/components/wp-relations/child-relations-handler/child-relations-handler.service.ts
@@ -0,0 +1,98 @@
+//-- copyright
+// OpenProject is a project management system.
+// Copyright (C) 2012-2015 the OpenProject Foundation (OPF)
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License version 3.
+//
+// OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+// Copyright (C) 2006-2013 Jean-Philippe Lang
+// Copyright (C) 2010-2013 the ChiliProject Team
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+//
+// See doc/COPYRIGHT.rdoc for more details.
+//++
+
+import {RelationsHandler} from "../relations-handler/relations-handler.service";
+import {opViewModelsModule} from "../../../angular-modules";
+import {HalResource} from "../../api/api-v3/hal-resources/hal-resource.service";
+
+var $state:ng.ui.IStateService;
+var WorkPackageService:any;
+var ApiNotificationsService:any;
+
+export class ChildRelationsHandler extends RelationsHandler {
+  public type:string = 'child';
+
+  public canAddRelation():boolean {
+    return !!this.workPackage.addChild;
+  }
+
+  public canDeleteRelation() {
+    return !!this.workPackage.update;
+  }
+
+  public addRelation() {
+    var params = {parent_id: this.workPackage.id, projectPath: this.workPackage.project.identifier};
+
+    if ($state.includes('work-packages.show')) {
+      $state.go('work-packages.new', params);
+    }
+    else {
+      $state.go('work-packages.list.new', params);
+    }
+  }
+
+  public getRelatedWorkPackage(relation:HalResource) {
+    return relation.$load();
+  }
+
+  public removeRelation(scope) {
+    var index = this.relations.indexOf(scope.relation);
+    var params = {
+      lockVersion: scope.relation.lockVersion,
+      parentId: null
+    };
+
+    WorkPackageService.updateWithPayload(scope.relation, params)
+      .then(response => {
+        scope.workPackage.lockVersion = response.lockVersion;
+
+        this.relations.splice(index, 1);
+        scope.updateFocus(index);
+        scope.$emit('workPackageRefreshRequired');
+      })
+      .catch(error => {
+        ApiNotificationsService.addError(error);
+      });
+  }
+}
+
+function childRelationsHandlerService(_$state_, _WorkPackageService_, _ApiNotificationsService_) {
+  $state = _$state_;
+  WorkPackageService = _WorkPackageService_;
+  ApiNotificationsService = _ApiNotificationsService_;
+
+  return ChildRelationsHandler;
+}
+
+childRelationsHandlerService.$inject = [
+  '$state',
+  'WorkPackageService',
+  'ApiNotificationsService'
+];
+
+opViewModelsModule.factory('ChildRelationsHandler', childRelationsHandlerService);
diff --git a/frontend/app/components/wp-relations/relations-handler/relations-handler.service.ts b/frontend/app/components/wp-relations/relations-handler/relations-handler.service.ts
index 46bbdf4d60..468e3910ce 100644
--- a/frontend/app/components/wp-relations/relations-handler/relations-handler.service.ts
+++ b/frontend/app/components/wp-relations/relations-handler/relations-handler.service.ts
@@ -26,7 +26,7 @@
 // See doc/COPYRIGHT.rdoc for more details.
 //++
 
-import {WorkPackageResource} from "../../api/api-v3/hal-resources/work-package-resource.service";
+import {WorkPackageResourceInterface} from "../../api/api-v3/hal-resources/work-package-resource.service";
 import {opViewModelsModule} from "../../../angular-modules";
 
 var $timeout:ng.ITimeoutService;
@@ -37,7 +37,7 @@ export class RelationsHandler {
   public type:string = 'relation';
   public isSingletonRelation:boolean = false;
 
-  constructor(public workPackage:WorkPackageResource, public relations, public relationsId) {
+  constructor(public workPackage:WorkPackageResourceInterface, public relations, public relationsId) {
   }
 
   public isEmpty() {
diff --git a/frontend/app/work_packages/view_models/children-relations-handler.js b/frontend/app/work_packages/view_models/children-relations-handler.js
deleted file mode 100644
index 2a975bbe7c..0000000000
--- a/frontend/app/work_packages/view_models/children-relations-handler.js
+++ /dev/null
@@ -1,78 +0,0 @@
-//-- copyright
-// OpenProject is a project management system.
-// Copyright (C) 2012-2015 the OpenProject Foundation (OPF)
-//
-// This program is free software; you can redistribute it and/or
-// modify it under the terms of the GNU General Public License version 3.
-//
-// OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
-// Copyright (C) 2006-2013 Jean-Philippe Lang
-// Copyright (C) 2010-2013 the ChiliProject Team
-//
-// This program is free software; you can redistribute it and/or
-// modify it under the terms of the GNU General Public License
-// as published by the Free Software Foundation; either version 2
-// of the License, or (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with this program; if not, write to the Free Software
-// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
-//
-// See doc/COPYRIGHT.rdoc for more details.
-//++
-
-module.exports = function(
-    CommonRelationsHandler,
-    WorkPackageService,
-    ApiNotificationsService,
-    $state
-  ) {
-  function ChildrenRelationsHandler(workPackage, children) {
-      var handler = new CommonRelationsHandler(workPackage, children, undefined);
-
-      handler.type = 'child';
-      handler.applyCustomExtensions = undefined;
-
-      handler.canAddRelation = function() { return !!this.workPackage.links.addChild; };
-      handler.canDeleteRelation = function() {
-        return !!this.workPackage.links.update;
-      };
-      handler.addRelation = function() {
-        var params = { parent_id: this.workPackage.props.id,
-                       projectPath: this.workPackage.embedded.project.props.identifier };
-        if ($state.includes('work-packages.show')) {
-          $state.go('work-packages.new', params);
-        }
-        else {
-          $state.go('work-packages.list.new', params);
-        }
-      };
-      handler.getRelatedWorkPackage = function(workPackage, relation) { return relation.fetch(); };
-      handler.removeRelation = function(scope) {
-          var index = this.relations.indexOf(scope.relation);
-          var handler = this;
-          var params = {
-            lockVersion: scope.relation.props.lockVersion,
-            parentId: null
-          };
-
-          WorkPackageService.updateWithPayload(scope.relation, params).then(function(response){
-              handler.relations.splice(index, 1);
-              scope.workPackage.props.lockVersion = response.props.lockVersion;
-              scope.updateFocus(index);
-              scope.$emit('workPackageRefreshRequired');
-          }, function(error) {
-            ApiNotificationsService.addError(error);
-          });
-      };
-
-      return handler;
-  }
-
-  return ChildrenRelationsHandler;
-};
diff --git a/frontend/app/work_packages/view_models/index.js b/frontend/app/work_packages/view_models/index.js
index 5e36f63eb8..acd821b0ac 100644
--- a/frontend/app/work_packages/view_models/index.js
+++ b/frontend/app/work_packages/view_models/index.js
@@ -27,13 +27,6 @@
 //++
 
 angular.module('openproject.viewModels')
-  .factory('ChildrenRelationsHandler', [
-    'CommonRelationsHandler',
-    'WorkPackageService',
-    'ApiNotificationsService',
-    '$state',
-    require('./children-relations-handler')
-  ])
   .factory('ParentRelationsHandler', [
     'CommonRelationsHandler',
     'WorkPackageService',