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# Option

Probably the most opinionated implementation of the Option type for TypeScript.

## Features:

-   Lazy and async versions of helpers:
    One of the goals of this lib is to provide variations of helpers which are lazy (don't compute something if it's not needed) or async (make mixing Promises and Options easier). If there is any function you want one of those variations of, be sure to open an issue:)
-   Large amount of helpers (curently 30), more than f#'s and elm's core libraries combined.
-   Typesafe:
    ```ts
    const foo0: Option<string> = None // works
    const foo1: Option<string> = Some('foo1') // works
    const foo2: Option<string> = 'foo2' // errors out
    const foo3: Option<string> = null // errors out
    const foo4: Option<string> = Some(4) // errors out
    ```
-   Reference equality:
    ```ts
    Some(7) === Some(7) // true
    Some(7) === Some(5) // false
    Some(7) === None // false
    ```

## Limitations

Both limitaions bellow come from the lack of nominal-typing offered by TypeScript and are inherited from the `Brand` type offered by the [utility-types](https://github.com/piotrwitek/utility-types) library

-   Due to the way the library works (using the `Brand`
    type from [utility-types](https://github.com/piotrwitezutility-types)) `Some(4) === 4` will return true, similarly to how `4 == "4"` returns true (except in this libraries case the `===` operator will behave the same way).
-   The inner value of `Option` cannot have a `__brand` prop
    (well, tehnically it can but it would be overwritten by the `Brand` type from [utility-types](https://github.com/piotrwitek/utility-types))

## Installation

```sh
npm install @adrielus/option
```

(There is also an amd build at `/dist/bundle.umd.js` which uses the `Option` namespace)

## Usage

For detailed usage read [the docs](https://github.com/Mateiadrielrafael/option/tree/master/docs/main.md)

> Note: The docs are still work in progress. Contributions are welcome:)

# Contributing

First, clone this repo:

```sh
git clone https://github.com/Mateiadrielrafael/option
cd option
```

Then use **_pnpm_** to install the dependencies:

```sh
pnpm install
```

You can use the `build` command to build the package (this is dont automatically by github actions):

```sh
pnpm run build
```