Question

当我在RegisterForm中输入电子邮件时，它等于将['emailTaken']设置为true的电子邮件。我收到以下错误代码：

ERROR TypeError: Cannot read property 'emailTaken' of null

这是我函数的代码：

checkEmail(control:FormControl): Promise<any> | Observable<any>{
    const answer = new Promise<any>((resolve, reject) => {
      setTimeout(() => {
        if(control.value == 'stijn.wauters@outlook.com'){
          resolve({'emailTaken': true})
        }else{
          resolve(null)
        }
      },1500);
    });
    return answer;
  }

在这里，我触发HTML中的错误：

<span *ngIf="registerForm.get('email').errors['emailTaken']" class="help-block">
                            Email is already taken!
                        </span>

如何解决此问题，以免出现错误？

Answer 1

您可以通过选中null。运算符

<span *ngIf="registerForm.get('email')?.errors['emailTaken']" class="help-block">
                            Email is already taken!
                        </span>

Answer 2

hasError对于检查错误可能更有用。

<span *ngIf="registerForm.get('email').hasError('emailTaken')" class="help-block">
       Email is already taken!
</span>

TypeError：无法读取null的属性'emailTaken'

2 个答案: