Question

一切正常，直到发生第二次接触为止。

TypeError: Cannot set property 'name' of undefined

因为构造函数中的默认联系人只有1次出现。有什么解决方法吗？

class Cust {
  constructor(custData) {

    this.address = {
      countryCode: null,
      address1: null,
      address2: null,
      city: null,
      countrySubDivision: null,
      postalCode: null
    },
    this.groupId = null;
    this.contact = [{ name: null, phone: null }];  
    //this.contact.phone = custData.contact.phone    
    this.state = this._getState(custData.status || null);

    this._setData(custData);
  }

  _getState(status) {
    let state = (status == 'active' ? 'good' : 'bad');
    return state;
  }
  _setData(data, prefix, index) {
    let result;
    for (let key in data) {
      let value = data[key];
      let valueIsNullOrEmpty = !value;
      if (!valueIsNullOrEmpty && typeof value === 'object') {
        if (Array.isArray(value)) {
          value = value
            .map((subProperty, index) => this._setData(subProperty, key, index))
            .filter((subProperty) => Object.keys(subProperty).length > 0);
          valueIsNullOrEmpty = value.length === 0;
          continue;
        } else {
          value = this._setData(value, key);
          valueIsNullOrEmpty = Object.keys(value).length === 0;
          continue;
        }
      }
      if (prefix) {
        if (index >= 0) {
          this[prefix][index][key] = data[key];
        }
        else {
          this[prefix][key] = data[key];
        }
      }
      else {
        this[key] = data[key]
      }
      result = data[key];

    }
    console.log(JSON.stringify(this));
    return result;
  }
}

var custData = {
  id: 1,
  name: "Barr",
  //  groupId: 2,
  status: "active",
  address: {
    countryCode: "USA",
    address1: "123 main street",
    address2: null,
    city: "Chicago",
    postalCode: "85001"
  }, contact: [
    {
      phone: "222-222-2222"
    },
    {
      name: "Tim"
    }]
}
var cust = new Cust(custData);

Answer 1

您正在递归地格式化数据，但始终尝试从this更改突变数据，例如

  this[key]

这将适用于深度1，但假设深度为5，它将变得复杂：

 this[key1][key2][key3][key4][key5]

您明白了这一点（这就是您的代码实际失败的地方，访问了深度大于2的嵌套对象的属性）。

this将永远无法使用。代替将对象修改为成方法（然后可以是函数），还可以通过返回新对象（使调试更加容易）来使其保持不变。

 function format(obj) {
    const result = {};
   //...
   return result;
 }

然后，您可以轻松地使用嵌套对象调用format。从类内部可以称为：

  Object.assign(this, format(data));

带数组的ES6类默认值

1 个答案: