Angular 4：使用自定义异步验证器将响应式表单控件置于挂起状态

我正在构建一个Angular 4应用程序，它需要在几个组件的表单字段上进行BriteVerify电子邮件验证 . 我正在尝试将此验证实现为可以与反应式表单一起使用的自定义异步验证器 . 目前，我可以获得API响应，但控制状态仍处于暂挂状态 . 我没有错，所以我有点困惑 . 请告诉我我做错了什么 . 这是我的代码 .

组件

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
}

Validator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（只是表格）

<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>