optional-js v2.3.0
Optional.js
A container object that wraps possibly undefined values in JavaScript - inspired by Java Optionals
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:
$ npm install optional-js
then just require in node:
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:
// "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...
$ node login.js root
"Logging in as : 1234"
Building
download:
git clone git@github.com:JasonStorey/Optional.js.git
enter the directory, and install dependencies:
cd Optional.js && npm install
build:
npm run build
Testing
run the tests:
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
5 years ago
6 years ago
6 years ago
7 years ago
7 years ago
7 years ago
9 years ago
9 years ago
9 years ago
10 years ago
10 years ago
10 years ago
10 years ago
10 years ago
11 years ago
11 years ago
11 years ago
11 years ago
11 years ago