代码之家 › 专栏 › 技术社区 › farahm

角度模型getter“不是函数”错误

google-cloud-firestore model function angular

0

farahm · 技术社区 · 7 年前

export class User {

   public username: string;
   private email: string;

   constructor() {
       this.username = undefined;
       this.email = undefined;
   }

   public getUsername(): string {
       return this.username;
   }

import {User} from '../../models/usermodel';

export classs ... {

   user: Observable<User | null>
   userCollection: AngularFirestoreCollection<User>;
   userLoadedFromFirestore: User[];

   this.userCollection = this.afs.collection('users', ref => ref.where('email', '==', this.sessionData.getUser().getEmail()));
   this.userCollection.valueChanges().subscribe((item => {
       this.userLoadedFromFirestore = item;
       this.userLoadedFromFirestore[0].getUsername();

用于访问 getUsername() 我得到运行时错误: is not a function . 为什么?当我这么做的时候 this.userLoadedFromFirestore[0].username

1 回复 | 直到 7 年前

1

0

Julius DzidzeviÄius 7 年前

将userLoadedFromFirestore类型设置为 User[] 类型,但当数据到达时,它不能保证该对象将是 User

subscribe(((item: User[]) => {

在你的情况下,你很可能需要:

this.userLoadedFromFirestore[0].username;

2

0

Iván Kollár 4 年前

在我的例子中,解决方案是将getter组织到对象外部。

export class UserData {

    public gid: string;
    
    //Error!
    public gidText(): string{
        return this.gid;
    }

}

解决方案:

export class UserService {

    public gidText(): string{
       return this.userData.gid;
    }

    export class UserData {
        public gid: string;
    }
}