tinyval

Tiny, fast, zero-dependency validation for browser and server.

• ~2.5 kB gzip for a typical form, ~5.5 kB for everything — only what you import ends up in the bundle
• TypeScript types inferred from the schema
• Nested objects and arrays, unknown keys handling, coercion, transforms, async checks

Install

npm install tinyval

Try it

Version local (0.1.1)

Quick start

import { validate, object, string, optional, pipe, trim, minLength, email, min, coerce, type Infer } from 'tinyval';

const User = object({
  name: pipe(string(), trim(), minLength(2)),
  email: pipe(string(), trim(), email()),
  age: optional(pipe(coerce.number(), min(0))),
});

type User = Infer<typeof User>; // { name: string; email: string; age?: number }

const result = validate(User, input);

if (result.valid) {
  result.data;   // cleaned, typed data
} else {
  result.errors; // { name: '...', email: '...' }
}

On the server parse is handier — it returns the data or throws ValidationError.

What's inside

Section	Contents
Functions	Running validation: validate, validateAsync, parse, parseAsync
Schemas	Data types: string, number, object, array, optional, union, variant, coerce…
Conditions	Like Laravel: requiredIf, requiredWith, requiredWithout, prohibitedIf
Object helpers	New schemas from existing ones: partial, pick, omit, extend
Rules	Checks and transforms via pipe: minLength, email, sameAs, trim, check…

Further reading

• Validation result — what's in data, errors and issues
• Empty values — why '' is treated as a missing value
• Messages & i18n — custom error texts and locales
• TypeScript — types from schemas
• Custom rules & schemas — when built-ins are not enough
• tinyval-vue — Vue forms: useForm, errors, submission, server errors
• Standard Schema — tinyval schemas in tRPC, Hono, TanStack Form, React Hook Form