Typed Schemas and Parsed Results

An Enforce schema can parse the input before the suite's tests run. Pass it as the second argument to create; the suite callback receives the parsed type and a successful result exposes the parsed value.

Define input and output together

import { create, enforce, test } from 'vest';

const registrationSchema = enforce.shape({
  age: enforce.isNumeric().toNumber(),
  newsletter: enforce.isBoolean(),
  username: enforce.isString().trim(),
});

export const registrationSuite = create(data => {
  // `data` is parsed output: age is a number and username is trimmed.
  test('username', 'Username is required', () => {
    enforce(data.username).isNotBlank();
  });

  test('age', 'You must be at least 18', () => {
    enforce(data.age).greaterThanOrEquals(18);
  });
}, registrationSchema);

The first rule in a parser chain determines the accepted input type. The final parser determines the output type. Here, age accepts a numeric string or number, while the suite callback receives a number.

Read the parsed result

const result = registrationSuite.run({
  age: '36',
  newsletter: true,
  username: '  Ada  ',
});

if (result.isValid()) {
  result.value;
  // { age: 36, newsletter: true, username: 'Ada' }
}

Use result.value only after a successful result. Invalid and pending results do not expose a valid parsed output.

Keep the execution APIs distinct

Situation	API
Interactive validation with retained state	registrationSuite.run(data)
Independent server request	registrationSuite.runStatic(data)
Compatible library expects Standard Schema	Pass registrationSuite to that library

Standard Schema consumers invoke the suite's ~standard.validate hook. Application code should continue using run() or runStatic() because those return Vest's full result with warnings, pending state, groups, focus, and selectors.

When implementing or testing a Standard Schema adapter directly, the contract is available explicitly:

const output = await registrationSuite['~standard'].validate({
  age: '36',
  newsletter: true,
  username: '  Ada  ',
});

Successful Standard Schema output contains the parsed values, so output.value.age is a number.

Using another schema library

Enforce can parse your API boundary, but it does not have to. If your application already uses Zod, Valibot, or another schema library there, keep it and use Vest for validation during interaction.

Read form and schema library integration, the Standard Schema reference, and the production registration architecture for complete compositions.