cross-tab-channel

This is a simple library for sending data between browser tabs. It uses storage events for same domain use, and adds in postMessage with an iframe for cross domain messaging. There is also a redux middleware.

Why this one?

There are a few of these, but none were what I wanted.

• Cross Domain
• Simplicity - the first release was 1.2k and under 50 lines of code. You get a channel that is an emitter. Nothing else.
• no OnBeforeUnload events - these events mess with the browser cache in undesireable ways that can make hitting the back button painful.

Usage

Same Domain

To use this library you listen to changes to a channel. A channel is identified with a string.

import CrossTab from 'cross-tab-channel';

var channel = new CrossTab('my-channel-name');

channel.listen(function (message) {
    console.log(message);
});

channel.emit({
    my: 'data'
});

channel.remove(anyPreviouslyAppliedListener);

You may emit messages of any type, as long as they can be JSON encoded.

Cross Domain

This is more tricky because the browser won't send storage events across domains. It needs to load an iframe hosted on your domain so the library can postMessages to and from it. Luckilly, that iframe has already been made and is entirely self contained.

import CrossDomain from 'cross-tab-channel/dist/CrossDomain';

// create the iframe that will serve as middleman between your domain and this one
// you can find iframe.html in the dist folder of this repo.
CrossDomain.createIframe('//your-domain.com/path/to/iframe.html');

// channel names are shared with normal, same domain, messaging.
var channel = new CrossDomain('my-channel-name');

channel.listen(function (message) {
    console.log(message);
});

channel.emit({
    my: 'data'
});

channel.remove(anyPreviouslyAppliedListener);

Testing

yarn start will start the dev server. Visit http://localhost/test.html and http://127.0.0.1/crossDomain.html and open the console to see it in action.

Browser Compatibility

Briefly tested on IE9 with surprisingly successful results.