Formify Docs

Composition

Combine validators with V.all, V.any, V.not, and V.optional

Composition

Individual validators cover one rule. Composition combines them so a single field can express AND, OR, NOT, and OPTIONAL logic.

Available combinators

FunctionBehavior
V.all([...rules], message?)Every rule must pass (AND). The message defaults to the first failing rule's message.
V.any([...rules], message?)At least one rule must pass (OR).
V.not(rule, message?)The rule must fail (NOT).
V.optional(rule)Only validate when non-empty — empty values always pass.

Examples

import { V } from "formify-js";

// AND: must be alphanumeric, 4–20 characters
const strongUsername = V.all([V.alphanumeric(), V.minLength(4), V.maxLength(20)]);

// OR: accept either an email or a phone number
const contact = V.any([V.email(), V.phone()], "Enter an email or a phone number");

// NOT: must not be the literal string "admin"
const notReserved = V.not(V.oneOf(["admin"]));

// OPTIONAL: only validated when the user typed something
const optionalUsername = V.optional(V.username());

Using composed rules in a schema

Composed rules are Rule objects, so they slot into a field's validators array alongside plain flags:

validationSchema: {
  contact: {
    required: true,
    validators: [
      { validator: V.any([V.email(), V.phone()]), message: "Enter an email or a phone number" },
    ],
  },
  username: {
    required: true,
    validators: [
      { validator: V.all([V.alphanumeric(), V.minLength(4), V.maxLength(20)]) },
    ],
  },
}

Default messages

Composed rules produce messages from their inner rules:

ScenarioMessage
V.all failsThe message of the first failing inner rule
V.any failsThe message argument, or a generic "must satisfy at least one rule" fallback
V.not failsThe inverse of the inner rule's message
V.optional with an empty valueNo error — empty values pass

Notes

  • V.optional is the composition-level equivalent of "validate only if filled in"; the required flag is the opposite — an empty value must fail.
  • Composition works in any field, including <FieldArray> items, because V returns plain validation rule objects.

On this page

CompositionAvailable combinatorsExamplesUsing composed rules in a schemaDefault messagesNotes