javascript - 类型错误 : Cannot read property 'first_name' of undefined on es6 model

Question

我想在 es6 模型中设置 JSON API，但收到此错误 类型错误:无法读取未定义的属性“first_name”

JSON API:

{      "type": "user",      "id": 2,      "attributes": {        "username": "madelynn81",        "email": "taylor63@mills.biz",        "first_name": "Emile",        "last_name": "Veum",        "created_at": "2018-11-17 11:48:13"      },      "links": {        "self": "http://test.test/api/v1/user/2"      }    }

es6 model

class UserModel {
    constructor(data) {
        this.id = data.id;
        this.first_name = data.attributes.first_name;
        this.last_name = data.attributes.last_name;
        this.username = data.attributes.username;
        this.email = data.attributes.email;
        this.created_at = data.attributes.created_at;
        this.link = data.links.self;
    }

    get getId() {
        return this.id;
    }

    set setId(value) {
        this.id = value;
    }

    get getFirstName() {
        return this.first_name;
    }

    set setFirstName(value) {
        this.first_name = value;
    }

    get getLastName() {
        return this.last_name;
    }

    set setLastName(value) {
        this.last_name = value;
    }

    get getUsername() {
        return this.username;
    }

    set setUsername(value) {
        this.username = value;
    }

    get getEmail() {
        return this.email;
    }

    set setEmail(value) {
        this.email = value;
    }

    get getCreatedAt() {
        return this.created_at;
    }

    set setCreatedAt(value) {
        this.created_at = value;
    }

    get getLink() {
        return this.link
    }

    set setLink(value) {
        this.link = value
    }
}

我该如何解决这个问题

Answer 1

从您的问题中不清楚您如何使用 getter 来获取值。一个问题:您的设置/获取对应该使用相同的属性名称来命名。它们的命名应与持有该值的属性不同。例如:_id 表示值属性名称，id 表示获取/设置名称。

class UserModel {

  constructor(data) {
    this._id = data.id;
    this._firstName = data.attributes.first_name;
  }

  get id() {
    return this.id;
  }

  set id(value) {
    this._id = value;
  }

  get firstName() {
    return this._firstName;
  }

  set firstName(value) {
    this._firstName = value;
  }

}
const data = {
  "type": "user",
  "id": 2,
  "attributes": {
    "username": "madelynn81",
    "email": "taylor63@mills.biz",
    "first_name": "Emile",
    "last_name": "Veum",
    "created_at": "2018-11-17 11:48:13"
  },
  "links": {
    "self": "http://test.test/api/v1/user/2"
  }
}

const user = new UserModel(data);
console.log(user.firstName)