javascript - Angular中唯一的用户名验证，数据返回服务的可观察类型

Question

// 注册页面.ts

  this.registerationForm = new FormGroup(
          {
            username: new FormControl(null,
              [
                Validators.required,
                Validators.minLength(3),
                Validators.maxLength(30),
                Validators.pattern('^[a-zA-Z-0123456789]*$'),
    
              ]
            ),

---

// accountService.ts

validateUsername(username: string): Observable<any> {
    return this.httpManager.post(authServer + "username-validator", new ValidateUsernameRequest(username)).pipe(
        map(
            (response: Response) => {
                return response.data;
            }
        )
    );
}

// 注册页面.html

<ion-item [ngClass]="username==null ? 'at-beginning':''">
                <ion-label position="floating">Kullanıcı Adı</ion-label>
                <ion-input name="username" formControlName="username" inputmode="text" class="ion-text-lowercase"
                  placeholder="Kullanıcı Adı" (onchange)=(checkUsername($event)) (keypress)=(onKeyUp($event)) (keydown.space)="$event.preventDefault()">
                </ion-input>
              </ion-item>

              <div class="err" *ngIf="formControls.username.errors">
                <div *ngIf="formControls.username.errors.required">Kullanıcı adı zorunlu.</div>
                <div *ngIf="formControls.username.errors.minlength">Kullanıcı adınız çok kısa.</div>
                <div *ngIf="formControls.username.errors.maxlength">Kullanıcı adınız çok uzun.</div>
                <div *ngIf="formControls.username.errors.pattern">Kullanıcı adınız özel karakter içeremez.</div>
                <div *ngIf="formControls.username.errors.checkUsername">Kullanıcı adınız alınmış.</div>
              </div>

我试图为用户名编写一个验证器，只要用户对输入进行更改，它就会检查其可用性。我已经为它奋斗了两天，但我只是卡住了。我知道我需要使用订阅数据的异步函数，accountService.validateUseranem(control.value)但不知何故我未能使其工作。

有人可以帮我吗？

标签： javascriptangulartypescriptionic-frameworkfrontend

Answer 1

我做了以下并解决了我自己的问题。

创建了 username-validator.directive.ts

import { AbstractControl,  AsyncValidatorFn, ValidationErrors } from '@angular/forms';
import { Observable, of } from 'rxjs';
import { map } from 'rxjs/operators';
import { AccountService } from 'src/app/services/yon/auth/account.service';

export function existingUsernameValidator(userService: AccountService): AsyncValidatorFn {
    return (control: AbstractControl): Promise<ValidationErrors | null> | Observable<ValidationErrors | null> => {
      return userService.validateUsername(control.value).pipe(map(
        (data) => {
            console.log("The result is : " + data)
          return (!data) ? { "usernameExists": true } : null;
        }
      ));
    };
  } 

然后在用户名的验证器中使用它

   this.registerationForm = new FormGroup(
          {
            username: new FormControl(null, {
              validators: [
                Validators.required,
                Validators.minLength(3),
                Validators.maxLength(20),
              ],
              asyncValidators: [existingUsernameValidator(this.accountService)],
              updateOn: 'change'
            }),
            email: new FormControl(null, {
              validators: [
                Validators.required,
                Validators.email],
              asyncValidators: [existingEmailValidator(this.accountService)],
              updateOn: 'change'
            }),

像这样

还;

updateOn: 'change' 了解该控件上的输入是否更改，并且每当输入更改时，它都会检查值以进行验证。

因为我需要向 API 发送请求并使用该值作为响应返回，所以我的验证器需要是一个异步验证器。据我所知，同步和aysnc验证器也需要分开，就像我做的那样。