option

Minimum option type port of Rust.

Background
Install
Usage
Documentation
Feature
API
Acknowledgements
Contributing
License

Background

This project provides minimum option features. They are designed to be optimized in tree-shaking.

One of the existing challenges in the JavaScript/TypeScript community is tree-shaking. Due to the dynamic nature of the language, tree-shaking can only be used in limited situations. That is, tree-shaking cannot do anything about unused class methods or properties.

The only solution to this is separation into top-level functions. It is very unfortunate but true that no other method exists.

Having said that, a future proposal could solve this.

Install

deno.land:

import * as mod from "https://deno.land/x/optio/mod.ts";

npm:

npm i @miyauci/option

Usage

Type Option represents an optional value.

Every Option is either Some and contains a value, or None, and does not.

import {
  expect,
  None,
  type Option,
  Some,
} from "https://deno.land/x/optio/mod.ts";

function divide(numerator: number, denominator: number): Option<number> {
  if (!denominator) return None;

  return Some(numerator / denominator);
}

const opt = divide(100, 0);
expect(opt, "divide by 0");

All operators for Option are separated from prototype.

Documentation

Operators

Feature

The pipeline operator will linearize the nesting.

import { map, type Option, match } from "https://deno.land/x/optio/mod.ts";

declare const option: Option<unknown>;
declare const mapper: (value: unknown) => unknown

const result = map(option, mapper)
  |> map(%, mapper)
  |> match(%, {
    Some: mapper,
    None:mapper
  })

proposal extensions allows for successive function adaptations, as in the Fluent API.

import { map, type Option, match } from "https://deno.land/x/optio/mod.ts";

declare const option: Option<unknown>;
declare const mapper: (value: unknown) => unknown

const result = option
  ::map(mapper)
  ::map(mapper)
  ::match({
    Some: mapper,
    None: mapper
  })

API

See deno doc for all APIs.

Acknowledgements

Rust std::option

Contributing

See contribution.