Wormhole

It's better EventEmitter for communication between tabs with supporting Master/Slave.

npm i --save-dev wormhole.js

Features

• One connection on WebSocket for all tabs.
• Support Master/Slave
• Cross-domain communication
• SharedWorker or fallback to localStorage
• IE 8+, Chrome 10+, FireFox 10+, Opera 10+, Safari 6+
• Test coverage (run)

---

Basic example

import wormhole from 'wormhole.js'; // yes, with ".js", it's not mistake

// All tabs
wormhole().on('coords', (x, y) => {
	console.log(x, y);
});

// Some tab
wormhole().emit('coords', [5, 10]);

// Master tab
if (wormhole().master) {
	// ..
}

wormhole().on('master', () => {
	console.log('Wow!');
});

---

One connection on WebSocket for all tabs

Module wormhole.js/ws implements WebSocket-like interface: https://rubaxa.github.io/wormhole/?ws=y

import WS from 'wormhole.js/ws';

// Create WebScoket (wormhole-socket)
const socket = new WS('ws://echo.websocket.org'); // OR new WS('...', null, hole);

socket.onopen = () => console.log('Connected');
socket.onmessage = ({data}) => console.log('Received:', data);

// Unique event
socket.onmaster = () => {
	console.log('Yes, I\'m master!');
};

// Some tab
socket.send({foo: 'bar'})

// All tabs:
//  "Received:" {foo: 'bar'}

---

CORS example

1. Create a subdomain, ex.: http://wormhole.youdomain.com/;
2. Copy-paste universal.html and wormhole.js into root;
3. Check access http://wormhole.youdomain.com/universal.html;
4. Profit:

// http://foo.youdomain.com/
import {Universal} from 'wormhole.js';
const hole = new Universal('http://wormhole.youdomain.com/universal.html');

hole.on('data', (data) => {
	console.log(data);
});


// http://bar.youdomain.com/
import {Universal} from 'wormhole.js';
const hole = new Universal('http://wormhole.youdomain.com/universal.html');

hole.emit('data', 'any data');

---

Master/slave example

import wormhole from 'wormhole.js';

// All tabs (main.js)
// Define remote command (master)
wormhole()['get-data'] = (function (_cache) {
	return function getData(req, callback) {
		if (!_cache.hasOwnProperty(req.url)) {
			_cache[req.url] = fetch(req.url).then(res => res.json());
		}

		return _cache[key];
	};
})({});

// Get remote data method
function getData(url) {
	return new Promise((resolve, reject) => {
		// Calling command on master (from slave... or the master, is not important)
		wormhole().call(
			'get-data', // command
			{url}, // arguments
			(err, json) => err ? reject(err) : resolve(json) // callback(err, result)
		);
	});
};

// I'm master!
wormhole().on('master', () => {
	// some code
});

// Tab #X
getData('/path/to/api').then((json) => {
	// Send ajax request
	console.log(result);
});

// Tab #Y
getData('/path/to/api').then((result) => {
	// From master cache
	console.log(result);
});

---

Peers

wormhole()
	.on('peers', (peers) => {
		console.log('ids:', peers); // ['tab-id-1', 'tab-id-2', ..]
	})
	.on('peers:add', (id) => {
		// ..
	})
	.on('peers:remove', (id) => {
		// ..
	})
;

---

Executing the command on master

// Register command (all tabs)
wormhole()['foo'] = (data, next) => {
	// bla-bla-bla
	next(null, data.reverse()); // or `next('error')`
};


// Calling the command (some tab)
wormhole().call('foo', [1, 2, 3], (err, results) => {
	console.log(results); // [3, 2, 1]
})

---

Modules

• Emitter — Micro event emitter
• cors — Handy wrapper over postMessage.
• store — Safe and a handy wrapper over localStorage.

---

wormhole.Emitter

Micro event emitter.

• on(type:String, fn:Function):this
• off(type:String, fn:Function):this
• emit(type:String[, args:*|Array]):this

import {Emitter} from 'wormhole.js';

const obj = Emitter.apply({}); // or new wormhole.Emitter();

obj.on('foo', () => {
  console.log(arguments);
});

obj.emit('foo'); // []
obj.emit('foo', 1); // [1]
obj.emit('foo', [1, 2, 3]); // [1, 2, 3]

---

wormhole.cors

Handy wrapper over postMessage.

import {cors} from 'wormhole.js';

// Main-document
cors.on('data', (data) => {
	console.log('Received:', data);
});

cors['some:command'] = (value) => value * 2;

// IFrame
cors(parent).send({foo: 'bar'});
// [main-document] "Received:" {foo: 'bar'}

cors(parent).call('some:command', 3, (err, result) => {
	console.log('Error:', err, 'Result:', result);
	// [iframe] "Error:" null "Result:" 6
});

---

wormhole.store

Safe and a handy wrapper over localStorage.

• get(key:String):*
• set(key:String, value:*)
• remove(key:String)
• on(type:String, fn:Function)
• off(type:String, fn:Function)

import {store} from 'wormhole.js';

store.on('change', (key, data) => {
	console.log('change -> ', key, data);
});

store.on('change:prop', (key, value) => {
	console.log('change:prop -> ', key, value);
});

store.set('foo', {bar: 'baz'});
// change -> foo {bar: 'baz'}

store.set('prop', {qux: 'ok'});
// change -> prop {qux: 'ok'}
// change:prop -> prop {qux: 'ok'}

---

Utils

• uuid
• debounce

---

wormhole.uuid():String

A universally unique identifier (UUID) is an identifier standard used in software construction, standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE) (c) wiki.

---

wormhole.debounce(fn:Function, delay:Number[, immediate:Boolean]):Function

Creates and returns a new debounced version of the passed function that will postpone its execution until after wait milliseconds have elapsed since the last time it was invoked.

---

Development

• npm test
• npm run dev — run dev watcher
• npm run build