Question

带有对象的复杂 Typescript 接口

2018-08-14

2353

angular typescript

我有一个定义为：

export interface Address {
    addressType: {
        house?: {
            streetAddress: string,
            city: string,
            zip: string,
        },
        apartment?: {
            streetAddress: "",
            unitNumber: "",
            city: "",
            zip: "",
            buildingName?: "",
        },
    }
    instructions?: string;
}

然后在我的组件的 Typescript 文件中，我定义了一个房屋地址：

address: Address;

constructor() {

    this.address.addressType = {
      house: {
        streetAddress: "1 test",
        city: "test city",
        zip: "92222",
      }
    }        
    console.log(this.address);
}

但是当我将地址记录到控制台时，我得到的是：

Uncaught (in promise): TypeError: Cannot set property 'addressType' of undefined

我以为我在构造函数中设置了 addressType。有没有更有效的方法来完成我正在做的事情？

Answer 1

您需要初始化 this.address 才能设置其 addressType：

constructor() {

    this.address = {
      addressType: {
        house: {
          streetAddress: "1 test",
          city: "test city",
          zip: "92222",
        }
      }
    };        
    console.log(this.address);
}

Answer 2

首先初始化您的 address 以引用一个对象。这将为您的对象提供内存，然后您可以初始化嵌套属性。

address: Address = { addressType: {} };

constructor() {

    this.address.addressType = {
      house: {
        streetAddress: "1 test",
        city: "test city",
        zip: "92222",
      }
    }        
    console.log(this.address);
}

Answer 3

您必须初始化 address 属性，因为注释任何具有类型的属性都不会提供值，并且它的初始值为 undefined 。

您可以像这样初始化您的属性

address: Address = { addressType: {} };

但我认为这里最好的方法是创建一个基于地址接口的类

export interface IAddress {
  addressType: {
    house?: {
      streetAddress: string,
      city: string,
      zip: string,
    },
    apartment?: {
      streetAddress: "",
      unitNumber: "",
      city: "",
      zip: "",
      buildingName?: "",
    },
  }
  instructions?: string;
}

class Address implements IAddress {
  addressType: { house?: { streetAddress: string; city: string; zip: string; }; 
  apartment?: { streetAddress: ""; unitNumber: ""; city: ""; zip: ""; buildingName?: ""; }; };
  instructions?: string;
  constructor() {
    this.addressType = {}; 
  }
}

您可以像这样使用它

address: Address = new Address();

house property of addressType is undefined

// this will throw an error can't read streetAddress of undefined
{{address.addressType.house.streetAddress}}

为了解决上述错误，您可以像 addressType

  constructor() {
    this.addressType = {}; 
    this.addressType.house = {}
  }


  一样初始化
  house