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BroadcastChannels: better

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Mahdi Dibaiee 2015-06-06 13:39:18 +04:30
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_posts/2015-04-02-broadcast-channel.md
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@ -16,7 +16,69 @@ your stars page in case you star something in another tab, right?
![Broadcast Channels, SATISFIED](/img/broadcast-channels.jpg)
#Let's Fix GitHub
#Show me something!
Okay, open another page of my blog in a new tab. Now open up your console and enter this:
{% highlight javascript %}
channel.postMessage('Anybody hears me?');
{% endhighlight %}
Boom.
I've put this code in my `<head>`, pretty simple:
{% highlight javascript %}
var channel = new BroadcastChannel('egg');
channel.addEventListener('message', message => {
alert('Got a message from the other tab:\n' + message.data);
// Egg
document.querySelector('header').classList.add('channel');
});
{% endhighlight %}
#How
BroadcastChannels are pretty easy, here I'm going over the small details.
##Creating channels
BroadcastChannels are constructed with a single argument, their name. Browsing contexts should use
this name to communicate over a specified channel. There's no limit to how many channels you can create.
In the first sentence of article I said it's used to communicate between tabs, but it's actually "browsing contexts".
[Browsing contexts](http://www.w3.org/TR/html5/browsers.html#browsing-context) are any environments owning a `Document`, e.g. tabs, windows, iframes, etc.
{% highlight javascript %}
var channel = new BroadcastChannel('star');
{% endhighlight %}
Channels have only one property, `name`.
##Methods
Channels have two methods:
### #postMessage(data: Anything)
This is the method used to broadcast a message to everyone subscribed to this channel. `data` can be any kind of Object.
### #close()
This method is used to leave a channel, in case you don't want to hear from the channel anymore.
Try leaving `channel` from my blog pages, and posting messages with others.
##Events
Channels inherit from [`EventTarget`](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget), so you can use `addEventListener`, `removeEventListener` and `dispatchEvent` methods.
Channels have only one event:
###message
The event object passed to this event is a [`MessageEvent`](https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent) with the `data` property set to the actual message sent using `postMessage`.
---
#Another example
##Let's Fix GitHub
Okay, let's try something cool, I promise you will love it. Open a browser with [BroadcastChannel support](http://caniuse.com/#feat=broadcastchannel) and Install [GreaseMonkey](http://www.greasespot.net/).
You have to add two scripts, one for repository pages, and one for the stars page.
@ -59,63 +121,6 @@ $('.starring-container form').submit(e => {
Save, refresh your pages and Voila! You can now Star/Unstar any repository while your stars page
is open, and your stars page will refresh immediately.
##I'm too lazy to try cool things, show me something!
Okay, open another page of my blog in a new tab. Now open up your console and enter this:
{% highlight javascript %}
channel.postMessage('Anybody hears me?');
{% endhighlight %}
Boom.
I've put this code in my `<head>`, pretty simple:
{% highlight javascript %}
var channel = new BroadcastChannel('egg');
channel.addEventListener('message', message => {
alert('Got a message from the other tab:\n' + message.data);
// Egg
document.querySelector('header').classList.add('channel');
});
{% endhighlight %}
#How
BroadcastChannels are pretty easy, here I'm going over the small details.
##Creating channels
BroadcastChannels are constructed with a single argument, their name. Browsing contexts should use
this name to communicate over a specified channel. There's no limit to how many channels you can create.
In the first sentence of article I said it's used to communicate between tabs, but it's actually "browsing contexts".
[Browsing contexts](http://www.w3.org/TR/html5/browsers.html#browsing-context) are any environments owning a `Document`, e.g. tabs, windows, iframes, etc.
{% highlight javascript %}
var channel = new BroadcastChannel('star');
{% endhighlight %}
Channels have only one property, `name`.
##Methods
Channels have two methods:
### #postMessage(data: Anything)
This is the method used to broadcast a message to everyone subscribed to this channel. `data` can be any kind of Object.
### #close()
This method is used to leave a channel, in case you don't want to hear from the channel anymore.
Try leaving `channel` from my blog pages, and posting messages with others.
##Events
Channels inherit from [`EventTarget`](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget), so you can use `addEventListener`, `removeEventListener` and `dispatchEvent` methods.
Channels have only one event:
###message
The event object passed to this event is a [`MessageEvent`](https://developer.mozilla.org/en-US/docs/Web/API/MessageEvent) with the `data` property set to the actual message sent using `postMessage`.
---
That's it, I really like this API as it's best of both worlds, simple and useful.