different

Validate that the field does not equal a sibling field's value.

Signature

NguardValidators.CrossField.different(
    fieldKey: string,
    isStrict?: boolean,
): ValidatorFn

Parameter	Type	Default	Description
fieldKey	string	—	The key of the sibling field
isStrict	boolean	false	If true, comparison uses === (strict). If false, == (loose, type coercion applies)

Reactive forms

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

const form = new FormGroup({
    oldEmail: new FormControl('user@old.com'),
    newEmail: new FormControl('', [
        NguardValidators.CrossField.different('oldEmail'),
    ]),
});

// Strict comparison (won't treat '1' and 1 as equal)
const strict = NguardValidators.CrossField.different('oldEmail', true);

Template-driven forms

<!-- Shorthand: pass the field key directly -->
<input ngModel name="newEmail" [nguardDifferent]="'oldEmail'" />

<!-- Object form: include strict mode -->
<input
    ngModel
    name="newEmail"
    [nguardDifferent]="{ fieldKey: 'oldEmail', isStrict: true }"
/>

Error key

{ different: true }

Notes

• With isStrict: false (default), '1' and 1 are considered equal — so a numeric 1 against string '1' fails this validator.
• With isStrict: true, the same case passes ('1' !== 1).
• If the control has no parent form group or the sibling has null / undefined, the validator passes (current value is "different" by definition).

See also

• same — opposite check
• confirmed — strict equality only, conventional naming for password-confirmation