Optional.js
===========

> A container object that wraps possibly undefined values in JavaScript - inspired by Java Optionals

`` javascript
Optional.ofNullable(promptForUserName)
.map(getUserId)
.filter(verify)
.ifPresent(login);
`

Features

- Runs in browser and Node
- Full Java 8 Optional API is supported, and partial Java 9 API implemented (everything minus stream())
- Zero dependencies
- TypeScript type definitions included
- Lightweight (<1.0 KB minified, gzipped)

Installation

Download the latest release from GitHub or from NPM

via npm:
` bash
$ npm install optional-js
`

then just require in node:
` javascript
const Optional = require('optional-js');
const emptyOptional = Optional.empty();
`

alternatively, use the browser compatible build in the ./dist directory of the npm package

Not using a module loader? Include the script, and the browser global Optional will be added to window.

Usage

Java docs - Java 9 Optionals
TSDocs - index.d.ts

JS Example:
` javascript
// "login.js"

const Optional = require('optional-js');

// Define some simple operations
const getUserId =
username => username === 'root' ? 1234 : 0;

const verify =
userId => userId === 1234;

const login =
userId => console.log('Logging in as : ' + userId);

// Declare a potentially undefined value
const username = process.argv[2];

// Wrap username in an Optional, and build a pipeline using our operations
Optional.ofNullable(username)
.map(getUserId)
.filter(verify)
.ifPresent(login);
`
Then, from the terminal...
` bash
$ node login.js root
"Logging in as : 1234"
``

Building

download:
` bash
git clone git@github.com:JasonStorey/Optional.js.git
`

enter the directory, and install dependencies:
`bash
cd Optional.js && npm install
`

build:
`bash
npm run build
`

Testing

run the tests:
`bash
npm test
``

Contributing

Found a bug or missing feature? Please open an issue!

Send your feedback. Send your pull requests. All contributions are appreciated!

License

Optional.js may be freely distributed under the MIT license - LICENSE