角度的电子邮件验证

Question

我正在尝试向电子邮件添加验证。

结构：使用响应式表单，获取电子邮件并使用过滤器 javascript 检查是否已存在。

component.ts:

  isUniqueEmail(): ValidatorFn {
    return (control: AbstractControl):  any | null => {
      if(control.value.email != null){
      this.httpService
      .getDataFromServer("api/employees?company_branch=" +this.user.branch_id)
      .subscribe((resp) => {
        var data = resp.data.employee;
        
        const found = data.filter(v => v.email == control.value.email);
  
        if(found.length !== 0){
          console.log("found one");
          return {exist: true}
        }
      });
      }
    }
  }

如果电子邮件已经存在 console.log 打印找到并且一切正常。

表单控件声明：

  this.employeeForm = new FormGroup({

    email: new FormControl(null,
       [
      Validators.required,
      Validators.pattern("^[a-z0-9._%+-]+@[a-z0-9.-]+\\.[a-z]{2,4}$"),
      ValidatorsSettings.notOnlyWhitespace,
       ]),

  ),{validators: this.isUniqueEmail()}}

在 html 中：

          <div class="row">
            <div class="from-group">
              <label for="Email"> Email </label>
              <mat-divider></mat-divider>

              <input
                type="text"
                id="Email"
                class="form-control"
                formControlName="email"
              />

              <div *ngIf="employeeForm.get('email').invalid && (employeeForm.get('email').touched || employeeForm.get('email').dirty)" class="help-block">
                <div *ngIf="employeeForm.get('email').errors.required || employeeForm.get('email').errors.notOnlyWhitespace" class="help-block">
                    Email is required
                </div>

                <div *ngIf="employeeForm.get('email').errors.pattern" class="help-block">
                    Email must be a valid email address format
                </div>

                <mat-error *ngIf="employeeForm.errors?.exist" class="help-block"
                >Email Already Exist</mat-error>

            </div>

            </div>
          </div>

错误未显示！我做错了什么？

Answer 1

由于验证器使用服务来请求响应，它应该是asyncValidator。代码最终可能是：

 isUniqueEmail(): AsyncValidatorFn {
    return (control: AbstractControl): Observable<ValidationErrors>=> {
      if(control.value.email != null){
        return this.httpService
        .getDataFromServer("api/employees?company_branch="+this.user.branch_id).pipe(
        .map((resp) => {
           var data = resp.data.employee;
           const found = data.filter(v => v.email == control.value.email);
           if(found.length !== 0){
             console.log("found one");
             return {exist: true}
           }
        });
      } 
      else return null;
    }
  }