Easy-to-use library that implements opaque types in TypeScript!
npm install ts-opaque[docs-url]: https://seancroach.github.io/ts-opaque/modules.html
[downloads-badge]: https://img.shields.io/npm/dt/ts-opaque?logo=npm
[opaque-types-url]: https://codemix.com/opaque-types-in-javascript/
[github-ci-badge]: https://img.shields.io/github/workflow/status/seancroach/ts-opaque/CI?logo=github
[github-ci-url]: https://github.com/seancroach/ts-opaque/actions?query=workflow%3A%22CI%22
[license-url]: https://github.com/seancroach/ts-opaque/blob/latest/license
[release-url]: https://www.npmjs.com/package/ts-opaque
[![Build Status][github-ci-badge]][github-ci-url] [![Downloads][downloads-badge]][release-url]
_Easy-to-use library that implements [opaque types][opaque-types-url] in TypeScript!_
Install ts-opaque through npm:
``
$ npm install ts-opaque
An opaque type, in TypeScript, is a type whose true structure is obfuscated to the compiler at compile-time. These types can make your code more type safe, secure, easier to refactor, and faster!
While Flow has an opaque keyword for creating opaque types, TypeScript does not; this package is my solution.
`ts
import Opaque from "ts-opaque";
interface User {
readonly id: Opaque
name: string;
}
interface Post {
readonly id: Opaque
readonly authorId: User["id"];
title: string;
body: string;
}
let myUser: User = {
// Error, type 'number' is not assignable to type 'Opaque
id: 1,
name: "John Doe",
};
myUser = {
id: 1 as User["id"],
name: "John Doe",
};
let myPost: Post = {
// Error, type 'number' is not assignable to type 'Opaque
id: 1,
// Error, type 'number' is not assignable to type 'Opaque
authorId: 1,
title: "ts-opaque",
body: "It's a pretty cool package.",
};
myPost = {
id: 1 as Post["id"],
authorId: myUser.id,
title: "ts-opaque",
body: "It's a pretty cool package.",
};
`
There are other types and helper function ts-opaque exports as well! Check out the API below.
- Opaque - Create an opaque type.
- BaseType - Get the base type of an opaque type.
- BrandType - Get the brand type of an opaque type.
- create - Cast a value to an opaque type.
- widen - Widen an opaque type to its base type.
Others have made fantastic packages to implement opaque types in TypeScript. While these implementations are flawless in their functionality, ts-opaque brands its opaque types with symbol keys, hiding them directly from your IDE's intellisense or its equivalent. ts-opaque is also distributed with helper functions and types to manipulate and use opaque types easily. Spread some love to these works:
This package is available as open source under the terms of the [MIT License][license-url].