negative

Validate that a numeric value is strictly less than zero.

Signature

NguardValidators.Number.negative: ValidatorFn

A parameterless validator — used directly without invocation.

Reactive forms

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

const temperature = new FormControl('', [NguardValidators.Number.negative]);

Template-driven forms

<input ngModel name="temperature" nguardNegative />

Error key

{ negative: true }

Notes

• The check is strict (< 0). Zero fails.
• Numeric strings work — '-5' passes; '0' fails.
• null, undefined, empty string, NaN, Infinity all fail.

See also

• positive — symmetric counterpart
• max — pass max(0) if you want to allow zero (<= 0 instead of < 0)