[英]Unique username validation in Angular with data returns type of observable from service
// register-page.ts //注册-page.ts
this.registerationForm = new FormGroup(
{
username: new FormControl(null,
[
Validators.required,
Validators.minLength(3),
Validators.maxLength(30),
Validators.pattern('^[a-zA-Z-0123456789]*$'),
]
),
// accountService.ts // accountService.ts
validateUsername(username: string): Observable<any> {
return this.httpManager.post(authServer + "username-validator", new ValidateUsernameRequest(username)).pipe(
map(
(response: Response) => {
return response.data;
}
)
);
}
// register-page.html //注册-page.html
<ion-item [ngClass]="username==null ? 'at-beginning':''">
<ion-label position="floating">Kullanıcı Adı</ion-label>
<ion-input name="username" formControlName="username" inputmode="text" class="ion-text-lowercase"
placeholder="Kullanıcı Adı" (onchange)=(checkUsername($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>
I've tried to code a validator for the username that checks its availability whenever the user make changes on the input.我尝试为用户名编写一个验证器,以便在用户对输入进行更改时检查其可用性。 I've fight for it two days but I'm just stuck.
我已经为它争取了两天,但我只是被卡住了。 I understood that I need to use an async function that subscribes the data came from
accountService.validateUseranem(control.value)
but somehow I failed to make it work.我知道我需要使用一个异步函数来订阅来自
accountService.validateUseranem(control.value)
的数据,但不知何故我未能使其工作。
Can someone help me on this?有人可以帮我吗?
I did the following and fixed my own problem.我做了以下并解决了我自己的问题。
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;
}
));
};
}
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'
}),
Also;还;
updateOn: 'change' Understands if the input changes on that control and whenever the input changes, it checks the value for validation. updateOn: 'change' 了解该控件上的输入是否发生变化,并且每当输入发生变化时,它都会检查值以进行验证。
And becasue that I need to send request to API and use that value returns as a response , my validator needed to be an asynchronous validator.因为我需要向 API 发送请求并使用该值返回作为响应,所以我的验证器需要是一个异步验证器。 Also the sync and aysnc validators need to be splitted as far as I understand, like I did.
据我所知,同步和 aysnc 验证器也需要分开,就像我所做的那样。
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