如何使用splice删除angularJS中的嵌套表单

我有一个嵌套表单…我可以很好地添加新字段，但删除字段时遇到一些问题

我希望能够拼接对象数组中的特定位置以删除字段

目前我有

html:

JSON:

---

将索引作为参数传递给函数

<div class="col-md-2">
   <a ng-click="removeCost($index)" class="btn btn-xs btn-danger">X</a>
</div>

attendees.removeCost = function(index){
            var cost = attendees.formData.scenarios[0].scenarioItems[index];
            if(cost.id) {
                cost._destroy = true;
            } else {
                attendees.cost.splice(index, 1);
            }


        var cost = attendees.formData.scenarios[0].scenarioItems[index];
};

"scenarioItems": [
        {
          "cost": "",
          "costDescription": "",
        },
        {
          "cost": "",
          "costDescription": ""
        },
        {
          "cost": "",
          "costDescription": ""
        },
        {
          "cost": "",
          "costDescription": ""
        }
      ]

<div class="col-md-2">
   <a ng-click="removeCost($index)" class="btn btn-xs btn-danger">X</a>
</div>

attendees.removeCost = function(index){
            var cost = attendees.formData.scenarios[0].scenarioItems[index];
            if(cost.id) {
                cost._destroy = true;
            } else {
                attendees.cost.splice(index, 1);
            }


        var cost = attendees.formData.scenarios[0].scenarioItems[index];
};