One Of

Validates that a value equals one of the items in a fixed list of allowed values. Useful for dropdowns, status fields, and single-choice questions.

Configuration

Config flag	Type	Description
`oneOf`	`unknown[]`	List of allowed values.
`oneOf`	`[unknown[], string]`	Tuple form — the list plus a custom message.

const form = useForm({
  initialValues: { status: '' },
  validationSchema: {
    status: { oneOf: ['active', 'paused', 'archived'] },
  },
});

With a custom message:

status: { oneOf: [['active', 'paused', 'archived'], 'Pick a valid status'] }

import { V } from 'formify-js';

V.oneOf(['active', 'paused', 'archived']);

Scenario	Message
Value is not in the list	`Must be one of: active, paused, archived` (the list is generated from your values)

Value	Rule	Result
`'active'`	`oneOf: ['active', 'paused']`	✅ Valid
`'deleted'`	`oneOf: ['active', 'paused']`	❌ Invalid

Comparison is strict (===) and case-sensitive: 'Active' fails when the list contains 'active'.
The default message names every allowed value, so users see exactly what is acceptable.
Use notOneOf when the requirement is the inverse (a blocklist).