Question

我对以下方法有疑问。我出现以下错误Cannot read property 'selectedMAP' of undefined。

const selectedPlan = {"name": "basic", "amount": 1000}
  let dependantsCost = 0;
  for (let i = 0; i < this.planCosts[0].selectedMAP.length; i++) {
   for (let j = 0; j < this.planCosts[0].selectedMAP[i].options.length; j++) {
    if (selection.medicalAid.numberOfAdultDependants > 0) {
       const costForAdultDependant = this.planCosts.filter(x => x.selectedMAP[i].options[j].optionName.toLowerCase() == selectedPlan.name.toLowerCase())[0].selectedMAP[i].options[j].adultDependantAmount;
       const numberOfAdultDependants = selection.medicalAid.numberOfAdultDependants;
       dependantsCost += numberOfAdultDependants * costForAdultDependant;
    } 
  }
}

这是我要过滤的数据集

[
  {
    "corporateId": "a682fafc-372a-4bbf-9b42-fe8b35cc437f",
    "selectedMAP": [
      {
        "mapId": 32,
        "mapName": "one",
        "active": true,
        "options": [
          {
            "optionId": 49,
            "optionName": "basic",
            "memberAmount": 1000,
            "adultDependantAmount": 500,
            "childDependantAmount": 500,
            "active": true
          },
          {
            "optionId": 50,
            "optionName": "advanced",
            "memberAmount": 2000,
            "adultDependantAmount": 1000,
            "childDependantAmount": 2000,
            "active": true
          }
        ]
      },
      {
        "mapId": 33,
        "mapName": "two",
        "active": true,
        "options": [
          {
            "optionId": 51,
            "optionName": "lite",
            "memberAmount": 1000,
            "adultDependantAmount": 500,
            "childDependantAmount": 500,
            "active": true
          },
          {
            "optionId": 52,
            "optionName": "heavy",
            "memberAmount": 2000,
            "adultDependantAmount": 500,
            "childDependantAmount": 500,
            "active": true
          }
        ]
      }
    ]
  }
]

this.planCosts [0]等于this

{
  "corporateId": "a682fafc-372a-4bbf-9b42-fe8b35cc437f",
  "selectedMAP": [
    {
      "mapId": 32,
      "mapName": "one",
      "active": true,
      "options": [
        {
          "optionId": 49,
          "optionName": "basic",
          "memberAmount": 1000,
          "adultDependantAmount": 500,
          "childDependantAmount": 500,
          "active": true
        },
        {
          "optionId": 50,
          "optionName": "advanced",
          "memberAmount": 2000,
          "adultDependantAmount": 1000,
          "childDependantAmount": 2000,
          "active": true
        }
      ]
    },
    {
      "mapId": 33,
      "mapName": "two",
      "active": true,
      "options": [
        {
          "optionId": 51,
          "optionName": "lite",
          "memberAmount": 1000,
          "adultDependantAmount": 500,
          "childDependantAmount": 500,
          "active": true
        },
        {
          "optionId": 52,
          "optionName": "heavy",
          "memberAmount": 2000,
          "adultDependantAmount": 500,
          "childDependantAmount": 500,
          "active": true
        }
      ]
    }
  ]
}

你知道为什么这会抛出一个错误吗？

Answer 1

此部分给出错误 this.planCosts.filter(...)[0].selectedMAP[i]，当滤波后的输出的长度变为零时。您可以像这样使用它来避免错误。

const lenOfFiltered = this.planCosts.filter(...).length;
if (lenOfFiltered ) {
    this.planCosts.filter(...)[0].selectedMAP[i].options[j].adultDependantAmount;
}

谢谢！

筛选器方法中的未定义属性

1 个答案: