Как инициализировать группу форм с помощью валидатора, но изначально без ошибок

Question

Я создаю новую группу форм с требуемым валидатором, но когда пользователь коснулся поля, элемент управления формы уже помечается как недействительный в начале.

const group: any = {};
group['subject'] = new FormControl(null, Validators.required);
const formGroup = new FormGroup(group);

<form [formGroup]="formGroup">
    <input matInput [formControlName]="subject" id="subject">
</form>

Я хочу сделать его недействительным только при размытииили грязныйКак я могу предотвратить это поведение?Спасибо.

Answer 1

Вы можете использовать реактивные формы, такие как:

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

// import custom validator to validate that password and confirm password fields match
import { MustMatch } from './_helpers/must-match.validator';

@Component({
    selector: 'app',
    templateUrl: 'app.component.html'
})

export class AppComponent implements OnInit {
    registerForm: FormGroup;
    submitted = false;

    constructor(private formBuilder: FormBuilder) { }

    ngOnInit() {
        this.registerForm = this.formBuilder.group({
            firstName: ['', Validators.required],
            lastName: ['', Validators.required],
            email: ['', [Validators.required, Validators.email]],
            password: ['', [Validators.required, Validators.minLength(6)]],
            confirmPassword: ['', Validators.required]
        }, {
            validator: MustMatch('password', 'confirmPassword')
        });
    }

    // convenience getter for easy access to form fields
    get f() { return this.registerForm.controls; }

    onSubmit() {
        this.submitted = true;

        // stop here if form is invalid
        if (this.registerForm.invalid) {
            return;
        }

        alert('SUCCESS!! :-)\n\n' + JSON.stringify(this.registerForm.value))
    }
}

и HTML-файл:

<!-- main app container -->
<div class="jumbotron">
    <div class="container">
        <div class="row">
            <div class="col-md-6 offset-md-3">
                <h3>Angular 7 Reactive Form Validation</h3>
                <form [formGroup]="registerForm" (ngSubmit)="onSubmit()">
                    <div class="form-group">
                        <label>First Name</label>
                        <input type="text" formControlName="firstName" class="form-control" [ngClass]="{ 'is-invalid': submitted && f.firstName.errors }" />
                        <div *ngIf="submitted && f.firstName.errors" class="invalid-feedback">
                            <div *ngIf="f.firstName.errors.required">First Name is required</div>
                        </div>
                    </div>
                    <div class="form-group">
                        <label>Last Name</label>
                        <input type="text" formControlName="lastName" class="form-control" [ngClass]="{ 'is-invalid': submitted && f.lastName.errors }" />
                        <div *ngIf="submitted && f.lastName.errors" class="invalid-feedback">
                            <div *ngIf="f.lastName.errors.required">Last Name is required</div>
                        </div>
                    </div>
                    <div class="form-group">
                        <label>Email</label>
                        <input type="text" formControlName="email" class="form-control" [ngClass]="{ 'is-invalid': submitted && f.email.errors }" />
                        <div *ngIf="submitted && f.email.errors" class="invalid-feedback">
                            <div *ngIf="f.email.errors.required">Email is required</div>
                            <div *ngIf="f.email.errors.email">Email must be a valid email address</div>
                        </div>
                    </div>
                    <div class="form-group">
                        <label>Password</label>
                        <input type="password" formControlName="password" class="form-control" [ngClass]="{ 'is-invalid': submitted && f.password.errors }" />
                        <div *ngIf="submitted && f.password.errors" class="invalid-feedback">
                            <div *ngIf="f.password.errors.required">Password is required</div>
                            <div *ngIf="f.password.errors.minlength">Password must be at least 6 characters</div>
                        </div>
                    </div>
                    <div class="form-group">
                        <label>Confirm Password</label>
                        <input type="password" formControlName="confirmPassword" class="form-control" [ngClass]="{ 'is-invalid': submitted && f.confirmPassword.errors }" />
                        <div *ngIf="submitted && f.confirmPassword.errors" class="invalid-feedback">
                            <div *ngIf="f.confirmPassword.errors.required">Confirm Password is required</div>
                            <div *ngIf="f.confirmPassword.errors.mustMatch">Passwords must match</div>
                        </div>
                    </div>
                    <div class="form-group">
                        <button class="btn btn-primary">Register</button>
                    </div>
                </form>
            </div>
        </div>
    </div>
</div>

Пользовательский валидатор:

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

// custom validator to check that two fields match
export function MustMatch(controlName: string, matchingControlName: string) {
    return (formGroup: FormGroup) => {
        const control = formGroup.controls[controlName];
        const matchingControl = formGroup.controls[matchingControlName];

        if (matchingControl.errors && !matchingControl.errors.mustMatch) {
            // return if another validator has already found an error on the matchingControl
            return;
        }

        // set error on matchingControl if validation fails
        if (control.value !== matchingControl.value) {
            matchingControl.setErrors({ mustMatch: true });
        } else {
            matchingControl.setErrors(null);
        }
    }
}

и вот полныйпример: ссылка