Angularfire2电子邮件认证引用承诺

Question

之外的变量我有这个组件：

export class LoginComponent { 
 
    login_error = ""; 
 

 
    constructor(public af: AngularFire) { 
 
    this.af.auth.subscribe(auth => console.log(auth)); 
 
    } 
 

 
    login(credentials) { 
 
     this.af.auth.login({ email: credentials.email, password: credentials.password}) 
 
     .catch(function (error) { 
 
     switch (error.code) { 
 
      case "INVALID_USER": 
 
      console.log("Invalid email"); 
 
      this.login_error = "Email is invalid"; //<----- broken 
 
      break; 
 

 
      case "INVALID_PASSWORD": 
 
      console.log("Invalid password"); 
 
      this.login_error = "Password is invalid"; //<----- broken 
 
      break; 
 

 
      default: 
 
      break; 
 
     } 
 
     }); 
 
    } 
 

 
    logout(){ 
 
    this.af.auth.logout(); 
 
    } 
 
}

我希望能够设置login_error变量（.catch内），这是在使用模板来通知用户他们的电子邮件或密码不正确，但我无法引用Promise之外的变量。有什么我做错了吗？还是有更好的方法来做我想要达到的目标？

Answer 1

我会使用箭头函数来代替。所以，你将能够（在此组件实例）使用上下文this：

login(credentials) { 
    this.af.auth.login({ email: credentials.email, password: credentials.password}) 
    .catch((error) => { // <------- 
    switch (error.code) { 
     case "INVALID_USER": 
     console.log("Invalid email"); 
     this.login_error = "Email is invalid"; 
     break; 

     case "INVALID_PASSWORD": 
     console.log("Invalid password"); 
     this.login_error = "Password is invalid"; 
     break; 

     default: 
     break; 
    } 
    }); 
}