io-ts-types

What is io-ts-types?

The io-ts-types package provides additional types and combinators for use with io-ts, a runtime type system for IO decoding/encoding in TypeScript. It extends the functionality of io-ts by offering more complex and useful types that are commonly needed in real-world applications.

What are io-ts-types's main functionalities?

DateFromISOString

This feature allows you to decode ISO string dates into JavaScript Date objects. It is useful for handling date strings in JSON APIs.

const { DateFromISOString } = require('io-ts-types');
const t = require('io-ts');

const DateType = DateFromISOString;

const result = DateType.decode('2023-10-01T00:00:00Z');
console.log(result); // Right(new Date('2023-10-01T00:00:00Z'))

NonEmptyString

This feature ensures that a string is not empty. It is useful for validating user input where empty strings are not allowed.

const { NonEmptyString } = require('io-ts-types');
const t = require('io-ts');

const NonEmptyStringType = NonEmptyString;

const result = NonEmptyStringType.decode('Hello');
console.log(result); // Right('Hello')

UUID

This feature validates that a string is a valid UUID. It is useful for ensuring that identifiers conform to the UUID format.

const { UUID } = require('io-ts-types');
const t = require('io-ts');

const UUIDType = UUID;

const result = UUIDType.decode('123e4567-e89b-12d3-a456-426614174000');
console.log(result); // Right('123e4567-e89b-12d3-a456-426614174000')

Option

This feature allows you to handle optional values in a functional way using the Option type from fp-ts. It is useful for dealing with nullable fields in a type-safe manner.

const { optionFromNullable } = require('io-ts-types');
const t = require('io-ts');

const OptionType = optionFromNullable(t.string);

const result = OptionType.decode(null);
console.log(result); // Right(none)

const result2 = OptionType.decode('Hello');
console.log(result2); // Right(some('Hello'))

Other packages similar to io-ts-types

zod

Zod is a TypeScript-first schema declaration and validation library. It provides a similar functionality to io-ts-types but with a different API and philosophy. Zod is more focused on developer experience and ease of use, while io-ts-types is more focused on functional programming paradigms.

yup

Yup is a JavaScript schema builder for value parsing and validation. It is similar to io-ts-types in that it provides a way to define and validate complex data structures. However, Yup is more widely used in the React ecosystem and has a more imperative API compared to the functional approach of io-ts-types.

superstruct

Superstruct is a library for validating and transforming data structures in JavaScript and TypeScript. It offers similar functionality to io-ts-types but with a simpler and more intuitive API. Superstruct is designed to be lightweight and easy to use, making it a good alternative for those who prefer a less functional approach.

README

A collection of runtime types and combinators for use with io-ts

Installation

To install the stable version:

npm i io-ts-types

Note. io-ts-types depends on

• fp-ts
• io-ts
• monocle-ts
• newtype-ts

starting from 0.5.0 you must install fp-ts, io-ts, newtype-ts and monocle-ts manually (fp-ts, io-ts, newtype-ts and monocle-ts are listed in peerDependency)

TypeScript compatibility

io-ts-types version	required typescript version
0.5.x	3.5+
0.4.x	3.1+

Documentation

• API Reference

Changelog

0.5.19

• New Feature
  • add mapFromEntries, readonlyMapFromEntries codecs, #172 (@mlegenhausen)