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shorterThan

Validate that a string is strictly shorter than another field's string.

Signature​

NguardValidators.String.shorterThan(fieldKey: string): ValidatorFn
ParameterTypeDescription
fieldKeystringThe key of the sibling field whose length is the target

Reactive forms​

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

const form = new FormGroup({
    fullName: new FormControl(''),
    abbreviation: new FormControl('', [
        NguardValidators.String.shorterThan('fullName'),
    ]),
});

Template-driven forms​

<input ngModel name="fullName" />
<input ngModel name="abbreviation" [nguardShorterThan]="'fullName'" />

Error key​

{ shorterThan: true }

Notes​

  • The check is strict (<). Equal lengths fail.
  • Both fields must be strings — non-string siblings cause failure.
  • If the control has no parent form group, the validator fails.

See also​