decimal

Validate that a number has a specific count of decimal places. Supports an exact form (decimal(2)) and an inclusive range form (decimal(1, 3)).

Signature

NguardValidators.Number.decimal(
    minPlaces: number,
    maxPlaces?: number,
): ValidatorFn

Parameter	Type	Default	Description
minPlaces	number	—	Required (or minimum) decimal places
maxPlaces	number	undefined	Optional maximum decimal places — present means range form

Reactive forms

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

// Exact: requires '1.23' (two decimal places)
const price = new FormControl('', [NguardValidators.Number.decimal(2)]);

// Range: accepts '1.2', '1.23', or '1.234' but rejects '1' or '1.2345'
const measurement = new FormControl('', [NguardValidators.Number.decimal(1, 3)]);

Template-driven forms

<!-- Exact form: pass a number -->
<input ngModel name="price" [nguardDecimal]="2" />

<!-- Range form: pass a [min, max] tuple -->
<input ngModel name="measurement" [nguardDecimal]="[1, 3]" />

Error key

{ decimal: true }

Notes

• Decimal place count is taken from the string representation: 1.5 has 1 decimal, 1.50 has 2 (when passed as the string '1.50').
• An integer value has 0 decimal places — decimal(0) accepts integers.
• Throws RangeValidatorErrors.MinGreaterThanMax if minPlaces > maxPlaces in range form.
• null, undefined, empty string, NaN, Infinity, non-numeric strings all fail.

See also

• numeric — type check without decimal-place constraint
• integer — equivalent to decimal(0)
• multipleOf — different precision concept (divisibility, not decimal-place count)