Option - API

Option represents an optional value: it is either some and contains a value, or none, and does not.

In contrast with the full-fledged Option<T> from fp-tp, this module provides just the bare minimum. If you require more features, consider using fp-tp.

Installation

npm

npm is the default package manager for Node.js, and to where tscommon is published.
Your project is using npm if it has a package-lock.json file in its root folder.

Run the following command in your terminal:

terminal

npm install @tscommon/option

yarn

yarn is a fast, reliable and secure dependency manager for Node.js.
Your project is using Yarn if it has a yarn.lock file in its root folder.

Run the following command in your terminal:

terminal

yarn add @tscommon/option

pnpm

pnpm is a fast, disk space efficient package manager for Node.js.
Your project is using pnpm if it has a pnpm-lock.yaml file in its root folder.

Run the following command in your terminal:

terminal

pnpm add @tscommon/option

Usage

Represent optional value

main.ts

import { None, Option, Some } from '@tscommon/option';

let data: Option<number> = Option.some(42);

if (Option.is(data, Some)) {
  // Data is present
}

data = Option.none;

if (Option.is(data, None)) {
  // Data is absent
}

Unwrap at least one array item

main.ts

import { Option } from '@tscommon/option';

Option.any([Option.some(1), Option.some(2)]);

// Output:
// Some { value: 1 }

Option.any([Option.some(1), Option.none]);

// Output:
// Some { value: 1 }

Unwrap all array items

main.ts

import { Option } from '@tscommon/option';

Option.all([Option.some(1), Option.some(2)]);

// Output:
// Some { value: [1, 2] }

Option.all([Option.some(1), Option.none]);

// Output:
// None {}