Integer

Validates that a value is an integer — a whole number with no decimal or fractional part. Negative integers and zero are accepted.

Configuration

Config flag	Type	Description
`integer`	`boolean`	When `true`, requires the value to be an integer.

const form = useForm({
  initialValues: { quantity: '' },
  validationSchema: {
    quantity: { integer: true },
  },
});

import { V } from 'formify-js';

V.integer();

Scenario	Message
Value is not a whole number	`Must be an integer`

Value	Result
`'42'`	✅ Valid
`'-3'`	✅ Valid
`'0'`	✅ Valid
`'4.5'`	❌ Invalid
`'4.0'`	❌ Invalid (decimal notation rejected)

Combine with min / max / between to constrain the accepted range.
A value like 4.0 fails because the decimal point is present; the check is on the literal value, not Number.isInteger coercion.