Skip to main content

@bodil/opt@0.2.2

latest
bodil/opt
Works with
It is unknown whether this package works with Bun
It is unknown whether this package works with Cloudflare Workers
This package works with Node.js
This package works with Deno
This package works with Browsers
JSR Score
58%
Published
3 weeks ago

opt

Option types for TypeScript with real gradual typing.

API Docs

Find the API docs here:

Rationale

There are several million implementations of option types on NPM. Many of them are implemented in plain JavaScript with no types. Nearly all of the remainder don't have very good type inference: their isSome() function just returns a boolean rather than a useful is assertion, or they exclusively use some other mechanism, like callbacks, to decide the type of the wrapped value. The very few cases remaining implement the option type as a simple object manipulated by external functions, rather than an object with attached methods, making them a little too cumbersome to work with.

This package gives you both, as well as a complete and fully documented API inspired by Rust's Option and Result types.

Example

Result in Node:

import { Ok, Result } from "@bodil/opt";

const result: Result<Date, Error> = Ok(new Date());

// result.value is Date | Error here.

if (result.isOk()) {
    // the type checker now knows that result.value must be a Date.
    console.log("Date:", result.value.toLocaleString());
} else {
    // the type checker knows result.value must be an Error in the else branch.
    console.log("Error:", result.value.message);
}

Option in Deno:

import { Option, Some } from "https://deno.land/x/opt/option.ts";

const option: Option<Date> = Some(new Date());

// option.value is Date | undefined here.

if (option.isSome()) {
    // the type checker now knows option.value is definitely a Date.
    console.log("Date:", option.value.toLocaleString());
} else {
    console.log("No value!");
}

Licence

Copyright 2023 Bodil Stokke

This software is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

Add Package

deno add @bodil/opt

Import symbol

import * as mod from "@bodil/opt";

Add Package

npx jsr add @bodil/opt

Import symbol

import * as mod from "@bodil/opt";

Add Package

yarn dlx jsr add @bodil/opt

Import symbol

import * as mod from "@bodil/opt";

Add Package

pnpm dlx jsr add @bodil/opt

Import symbol

import * as mod from "@bodil/opt";

Add Package

bunx jsr add @bodil/opt

Import symbol

import * as mod from "@bodil/opt";