指令控制器中的AngularJS表单属性

Question

我已经创建了指令信用卡

视图：credit-card.html

<form name="form" novalidate="" id="creditCardAmountInputForm" ng-submit="submit()">
  <div class="form-group col-md-5" ng-class="{ 'has-error': form.$submitted && form.amount.$invalid }">
    <div class="input-group">
      <input type="number" class="form-control" placeholder='{{ "dashboard.buyer.home.wallet_to_wallet.placeholders.amount" | translate }}'
    ng-model="transaction.amount" cent-number="" name="amount" required="" server-error="" max="2500">
   </div>
  </div>
  <div class="col-md-3">
    <button ng-disabled="user.status != 'activated'" type="submit" ladda="loading" class="btn btn-primary btn-block">{{ "dashboard.buyer.home.wallet_to_wallet.submit" | translate }}</button>
  </div>
</form>

控制器：`credit-card.coffee``

angular.module 'App'
  .directive 'creditCard', ->
    restrict: 'E',
    templateUrl: 'views/partials/credit-card.html'
    controller: ($rootScope, $scope, ENV, $window, transaction, notifications) ->
      $scope.user = $rootScope.user
      $scope.wallet = $scope.user.user_wallets[0]
      $scope.transaction = {}

      $scope.submit = ->
        new transaction(
          receiver_id: $scope.user.wallet_uuid
          amount: $scope.transaction.amount
          currency: "EUR"
       )

我面临的问题是属性$scope.transaction.amount未定义。

任何帮助将不胜感激

迈克