我使用Angular2创建了一个表单,并创建了以下方法来检查电子邮件地址是否已存在。这是我的代码:
checkEmail(): void {
// FIRST PART
this.found = false;
// If user is not Premium...
if (!this.currentUser.isPremium) {
// ...and if user typed something in the input field, then apply validitor for email address
if (this.myForm.controls.email.value.length > 0) {
this.myForm.controls.email.setValidators([validateEmail()]);
this.myForm.controls.email.updateValueAndValidity();
// If user leaves the input field blank or empty the typed input, then apply validator for required
} else {
this.myForm.controls.email.setValidators([Validators.required]);
this.myForm.controls.email.updateValueAndValidity();
}
// If user is Premium...
} else if (this.currentUser.isPremium) {
// ...and if user typed something in the input field, then apply validitor for email address
if (this.myForm.controls.email.value.length > 0) {
this.myForm.controls.email.setValidators([validateEmail()]);
this.myForm.controls.email.updateValueAndValidity();
// If user leaves the input field blank or empty the typed input, then remove any validator
} else {
this.myForm.controls.email.setValidators(null);
this.myForm.controls.email.updateValueAndValidity();
}
}
// SECOND PART
// If the input field is valid then check if the email already exist on server...
if (this.myForm.controls.email.value.length > 0 && this.myForm.controls.email.valid) {
this.loadingIcon = true;
this.anagraficaService.getEmail(this.myForm.controls.email.value)
.then(response => {
let count = response.recordCount;
if (count > 0) {
this.found = true;
} else {
this.found = false;
}
this.loadingIcon = false;
})
.catch(error => {
this.found = false;
this.loadingIcon = false;
});
}
}
要启用模板文件中的“提交”按钮,我会检查myForm.valid
并将found
设置为false
:
<button type="submit" class="ui primary button" (click)="onSubmit()" [disabled]="!myForm.valid || found">Submit</button>
现在,我想查看电子邮件地址(如果已存在),我的意思是将我的代码的第二部分放在外部文件(自定义验证程序)中,然后仅在我的代码的第一部分检查电子邮件地址的有效性。像这样:
this.myForm.controls.email.setValidators([validateEmail(), checkEmailExists()]);
this.myForm.controls.email.updateValueAndValidity();
您是否有更好的想法来达到相同的验证?有关此问题的最佳做法吗?
谢谢。
答案 0 :(得分:1)
哇。这远远不是反应形式验证的想法。
首先不要这样做
this.myForm.controls.email.setValidators([validateEmail()]);
this.myForm.controls.email.updateValueAndValidity();
setValidators
和updateValueAndValidity
是您几乎从不打电话的功能。它们仅适用于某些特定情况,如动态表单行为。
在您的情况下,您有一个静态表单,您应该描述一些验证器。创建自定义异步验证程序并将其分配给email
FormControl
。此验证器应返回一个Observable(或Promise),当一切正常时,它会解析为null
,或者对于有错误的对象,例如, { emailAlreadyExists: true }
如果电子邮件存在,{ required: true }
或使用Validators.required
和您的自定义异步验证的组合。
在一天结束时你应该
...
public ngOnInit() {
this.myForm = new FormGroup({
email: new FormControl('', null, (control: FormControl) => {
return new Promise((resolve, reject) => {
// also add here is premium logic
let requiredValidationResult = Validators.required(control);
if (requiredValidationResult) {
resolve(requiredValidationResult); // this will be {required: true}
return;
}
// and here call your server and call
// resolve(null) in case it's fine
// resolve({ emailExists: true }) in case it's existing
});
})
});
}
...
那就是它。