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Version: 0.10.0

requiredWith

The field is required when any of the listed sibling fields is filled.

Signature​

NguardValidators.CrossField.requiredWith(...fieldKeys: string[]): ValidatorFn
ParameterTypeDescription
fieldKeys...stringOne or more sibling keys. The rule applies as soon as one of them is filled

Reactive forms​

import { FormControl, FormGroup } from '@angular/forms';
import { NguardValidators } from 'ng-nguard';

// 'cardNumber' is required as soon as either 'billingAddress' or 'phone' is filled
new FormGroup({
    billingAddress: new FormControl(''),
    phone: new FormControl(''),
    cardNumber: new FormControl('', [
        NguardValidators.CrossField.requiredWith('billingAddress', 'phone'),
    ]),
});

Template-driven forms​

<!-- Single sibling -->
<input ngModel name="cardNumber" [nguardRequiredWith]="'phone'" />

<!-- Multiple siblings -->
<input
    ngModel
    name="cardNumber"
    [nguardRequiredWith]="['billingAddress', 'phone']"
/>

Error key​

{ requiredWith: true }

Notes​

  • "Filled" means the sibling's value is truthy (non-empty string, non-zero number, non-null/undefined).
  • The rule triggers when any of the listed siblings is filled — for the all-must-be-filled variant see requiredWithAll.
  • When the control has no parent form group, no sibling is reachable so the rule never triggers and the field can be empty.

See also​