Easy-to-use library that implements opaque types 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.
import Opaque from "ts-opaque";
interface User {
readonly id: Opaque<number, User>;
name: string;
}
interface Post {
readonly id: Opaque<number, Post>;
readonly authorId: User["id"];
title: string;
body: string;
}
let myUser: User = {
// Error, type 'number' is not assignable to type 'Opaque<number, User>'
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<number, Post>'
id: 1,
// Error, type 'number' is not assignable to type 'Opaque<number, User>'
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.
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.