Angular 4：反应式表单控件被自定义异步验证器卡在挂起状态

Question

我正在构建一个 Angular 4 应用程序，它需要对多个组件中的表单字段进行 BriteVerify 电子邮件验证。我正在尝试将此验证实现为自定义异步验证器，我可以将其与反应式表单一起使用。目前可以获取API响应，但是控件状态卡在pending状态。我没有收到任何错误，所以我有点困惑。请告诉我我做错了什么。这是我的代码。

零件

 import { Component,
         OnInit } from '@angular/core';
import { FormBuilder,
         FormGroup,
         FormControl,
         Validators } from '@angular/forms';
import { Router } from '@angular/router';

import { EmailValidationService } from '../services/email-validation.service';

import { CustomValidators } from '../utilities/custom-validators/custom-validators';

@Component({
    templateUrl: './email-form.component.html',
    styleUrls: ['./email-form.component.sass']
})

export class EmailFormComponent implements OnInit {

    public emailForm: FormGroup;
    public formSubmitted: Boolean;
    public emailSent: Boolean;

    constructor(
        private router: Router,
        private builder: FormBuilder,
        private service: EmailValidationService
    ) { }

    ngOnInit() {

        this.formSubmitted = false;
        this.emailForm = this.builder.group({
            email: [ '', [ Validators.required ], [ CustomValidators.briteVerifyValidator(this.service) ] ]
        });
    }

    get email() {
        return this.emailForm.get('email');
    }

    // rest of logic
}

验证器类

 import { AbstractControl } from '@angular/forms';

import { EmailValidationService } from '../../services/email-validation.service';

import { Observable } from 'rxjs/Observable';

import 'rxjs/add/observable/of';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/switchMap';
import 'rxjs/add/operator/debounceTime';
import 'rxjs/add/operator/distinctUntilChanged';

export class CustomValidators {

    static briteVerifyValidator(service: EmailValidationService) {
        return (control: AbstractControl) => {
            if (!control.valueChanges) {
                return Observable.of(null);
            } else {
                return control.valueChanges
                    .debounceTime(1000)
                    .distinctUntilChanged()
                    .switchMap(value => service.validateEmail(value))
                    .map(data => {
                        return data.status === 'invalid' ? { invalid: true } : null;
                    });
            }
        }
    }
}

服务

 import { Injectable } from '@angular/core';
import { HttpClient,
         HttpParams } from '@angular/common/http';

interface EmailValidationResponse {
    address: string,
    account: string,
    domain: string,
    status: string,
    connected: string,
    disposable: boolean,
    role_address: boolean,
    error_code?: string,
    error?: string,
    duration: number
}

@Injectable()
export class EmailValidationService {

    public emailValidationUrl = 'https://briteverifyendpoint.com';

    constructor(
        private http: HttpClient
    ) { }

    validateEmail(value) {
        let params = new HttpParams();
        params = params.append('address', value);
        return this.http.get<EmailValidationResponse>(this.emailValidationUrl, {
            params: params
        });
    }
}

模板（只是形式）

 <form class="email-form" [formGroup]="emailForm" (ngSubmit)="sendEmail()">
    <div class="row">
        <div class="col-md-12 col-sm-12 col-xs-12">
            <fieldset class="form-group required" [ngClass]="{ 'has-error': email.invalid && formSubmitted }">
                <div>{{ email.status }}</div>
                <label class="control-label" for="email">Email</label>
                <input class="form-control input-lg" name="email" id="email" formControlName="email">
                <ng-container *ngIf="email.invalid && formSubmitted">
                    <i class="fa fa-exclamation-triangle" aria-hidden="true"></i>&nbsp;Please enter valid email address.
                </ng-container>
            </fieldset>
            <button type="submit" class="btn btn-primary btn-lg btn-block">Send</button>
        </div>
    </div>
</form>

原文由 Andre Kuzmicheff 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

有个 陷阱！

也就是说，您的可观察对象永远不会完成…

发生这种情况是因为可观察对象永远不会完成，因此 Angular 不知道何时更改表单状态。所以请记住您的可观察对象必须完成。

您可以通过多种方式完成此操作，例如，您可以调用 first() 方法，或者如果您正在创建自己的可观察对象，则可以调用观察者的完整方法。

所以你可以使用 first()

更新到 RXJS 6：

 briteVerifyValidator(service: Service) {
  return (control: AbstractControl) => {
    if (!control.valueChanges) {
      return of(null);
    } else {
      return control.valueChanges.pipe(
        debounceTime(1000),
        distinctUntilChanged(),
        switchMap(value => service.getData(value)),
        map(data => {
          return data.status === 'invalid' ? { invalid: true } : null;
        })
      ).pipe(first())
    }
  }
}

一个稍微修改过的验证器，即总是返回错误： STACKBLITZ

---

老的：

 .map(data => {
   return data.status === 'invalid' ? { invalid: true } : null;
})
.first();

一个稍微修改过的验证器，即总是返回错误： STACKBLITZ

原文由 AT82 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

所以我所做的是在未使用用户名时抛出 404，并使用订阅错误路径解析为 null，当我确实收到响应时，我解决了一个错误。另一种方法是返回一个数据属性，要么填充用户名的宽度，要么通过响应对象为空，并使用 404 的 insead

前任。

在此示例中，我绑定 (this) 以便能够在验证器函数中使用我的服务

我的组件类 ngOnInit() 的摘录

//signup.component.ts

constructor(
 private authService: AuthServic //this will be included with bind(this)
) {

ngOnInit() {

 this.user = new FormGroup(
   {
    email: new FormControl("", Validators.required),
    username: new FormControl(
      "",
      Validators.required,
      CustomUserValidators.usernameUniqueValidator.bind(this) //the whole class
    ),
    password: new FormControl("", Validators.required),
   },
   { updateOn: "blur" });
}

我的验证器类的摘录

//user.validator.ts
...

static async usernameUniqueValidator(
   control: FormControl
): Promise<ValidationErrors | null> {

 let controlBind = this as any;
 let authService = controlBind.authService as AuthService;
 //I just added types to be able to get my functions as I type

 return new Promise(resolve => {
  if (control.value == "") {
    resolve(null);
  } else {
    authService.checkUsername(control.value).subscribe(
      () => {
        resolve({
          usernameExists: {
            valid: false
          }
        });
      },
      () => {
        resolve(null);
      }
    );
  }
});

...

原文由 Miguel Angel Romero Hernandez 发布，翻译遵循 CC BY-SA 4.0 许可协议