Update multiple files from AngularJs

file.controller.js

angular.module('starter.controllers', [])
.controller('TestCtrl', TestCtrl);

TestCtrl.$inject = ['updateService'];
function TestCtrl(updateService){
  var vm = this;
  vm.addImage = addImage;
  vm.data = {};

  function addImage() {
    var file = vm.data.myFile;
    console.log('file is ');
    console.dir(file);
    updateService.uploadFiles(file);
  }
}

file.directive.js

angular.module('starter', [])
  .directive('fileModel', ['$parse', function ($parse) {
    return {
      restrict: 'EA',
      link: function(scope, element, attrs) {
        var model = $parse(attrs.fileModel);
        var isMultiple = attrs.multiple;
        var modelSetter = model.assign;

        element.bind('change', function(){
          var values = [];
          angular.forEach(element[0].files, function (item) {
            // var value = {
            //  // File Name
            //   name: item.name,
            //   //File Size
            //   size: item.size,
            //   //File URL to view
            //   url: URL.createObjectURL(item),
            //   // File Input Value
            //   _file: item
            // };
            values.push(item);
          });
          scope.$apply(function () {
            if (isMultiple) {
              modelSetter(scope, values);
            } else {
              modelSetter(scope, values[0]);
            }
          });
        });
      }
    };
  }])

file.service.js

angular.module('starter.services', [])
  .factory('MantenimientosService', MantenimientosService);

MantenimientosService.$inject = ['BASE_URL', '$http'];
function MantenimientosService(BASE_URL, $http) {
    return {
      uploadFiles: uploadFiles
    };

    function uploadFiles(file) {
      var fd = new FormData();
      for (var key in file) {
        fd.append('file', file[key]);
      }
      var url = BASE_URL + '/uploadPhotos';
      $http.post(url, fd, {
        transformRequest: angular.identity,
        headers: {'Content-Type': undefined},
        withCredentials: false
      })
      .then(log)
      .catch(log);

      function log(data){
        console.log(data);
      }
    }
}

template.html

      <form>
        <input type="file" file-model="vm.data.myFile" multiple>
        <button type="button" class="button button-energized" ng-click="vm.addImage()">
          Add image
        </button>
      </form>

    {{vm.data}}