Instantiating angular js controller

myApp.js

    angular.module("myApp" , [subApp1]); //line1

subapp1.js

import mycontroller from './mycontroller';
 angular.module("subApp1",[])
 .config(['$stateProvider','$urlRouteProvider',function($stateProvider,$urlRouteProvider){
 $stateProvider.state('home', {
                                        url:'/home',
                                        templateUrl: './app/home.html',
                                        controller : myController //line 2
                        });
}])
.controller('myController',['$scope','$http', myController]]); //line 3

Issue :

Following is my home.html. Grid is directive that is working fine if i source data from json using ajax.but not working if i get scope data (same json) from controller.

<grid data-type="scope" data="mydata"></dashgrid>

In controller am getting data using $http.get that is working fine.but still its not getting populated in grid.

Error:  Uncaught (in promise) TypeError: Caot read property 'columns' of undefined(…)

Questions: 1)Is http get asynchronous ? whether grid getting loaded before actually data is loaded by $http.get 1) In this case when the controller will get instantiated (line1 or line 2 or line3 )? 2) what is difference between line 2 and line 3 ? Is line 3 necessary ?