channel-emitter

Installation

npm i --save channel-emitter

What is ChannelEmitter?

• A "singleton" EventEmitter - at its core it is a pseudo-singleton (it relies on the node module cache) EventEmitter. Every module within a process that requires ChannelEmitter will recieve the same cached object.
• A multi-channel emitter - ChannelEmitter supports channels as well as sub-channels. This allows listeners for an event on specific channels as well as emitting up to parent channels and broadcasting down to sub-channels.

Features

• Provides a "singleton" (a node module cached object).
• Allows name-spacing of events through "channels".
• Every channel can have multiple sub-channels.
• A channel can emit to all events on the channel as well as up to all parent channels.
• A channel can broadcast to all events on the channel as well as down to all sub-channels.

Examples

Basic Usage

As a singleton

/* a.js */
var channelEmitter = require('channel-emitter');
channelEmitter.on('foo', function () { console.log(arguments); });

/* b.js */
var channelEmitter = require('channel-emitter');
channelEmitter.emit('foo', true, {foo: []}, 123);

/* c.js */
require('./a');
require('./b');
// outputs: { '0': true, '1': { foo: [] }, '2': 123 }

With channels

/* a.js */
var channelEmitter = require('channel-emitter');
channelEmitter.on('foobar', function () { console.log('foobar: ', arguments); });
channelEmitter.on('foo.bar', function () { console.log('foo.bar: ', arguments); });

channelEmitter.emit('foobar', 'hi');
// returns true;
// outputs: foobar: { 0: 'hi' }

channelEmitter.emit('bar', 'hello');
// returns false;
// outputs:

channelEmitter.emit('foo.foobar', 'hi');
// returns true;
// outputs: foobar: { 0: 'hi' }

channelEmitter.emit('foo.bar', 'hello');
// returns true;
// outputs: foo.bar: { 0: 'hello' }

channelEmitter.broadcast('foobar', 'hi');
// returns true;
// outputs: foobar: { 0: 'hi' }

channelEmitter.broadcast('bar', 'hello');
// returns true;
// outputs: foo.bar: { 0: 'hello' }

channelEmitter.broadcast('foo.foobar', 'hi');
// returns false;
// outputs:

channelEmitter.broadcast('foo.bar', 'hello');
// returns true;
// outputs: foo.bar: { 0: 'hello' }

API Reference

Example

var channel_emitter = require('channel-emitter');

channel-emitter~addListener(eventName, listener) ⇒ ChannelEmitter

Wrapper for the EventEmitter.addListener method that will auto-add channels if the specified delimiter is used in the name.

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | eventName | string | the name for the event | | listener | function | the listener for the event |

channel-emitter~removeListener(eventName, listener) ⇒ ChannelEmitter

Wrapper for the EventEmitter.removeListener method that will remove events from a specified channl if the specified delimiter is used in the name.

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | eventName | string | the name for the event | | listener | function | the listener for the event |

channel-emitter~removeAllListeners([eventName]) ⇒ ChannelEmitter

Wrapper for the EventEmitter.removeAllListeners method that will remove if the specified delimiter is used in the name.

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | [eventName] | string | the name for the event |

channel-emitter~listenerCount(eventName) ⇒ ChannelEmitter

Wrapper for the EventEmitter.listenerCount method that will return the listener count on a channel (including name-spaced events).

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | eventName | string | the name for the event |

channel-emitter~listeners(eventName) ⇒ ChannelEmitter

Wrapper for the EventEmitter.listeners method that will return the listeners on a channel (including name-spaced events).

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | eventName | string | the name for the event |

channel-emitter~on(eventName, listener) ⇒ ChannelEmitter

Wrapper for the EventEmitter.on method that will auto-add channels if the specified delimiter is used in the name.

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | eventName | string | the name for the event | | listener | function | the listener for the event |

channel-emitter~addChannel(channelName) ⇒ ChannelEmitter

Adds a sub-channel to the current channel.

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | channelName | string | the name for the channel |

channel-emitter~removeChannel(channelName) ⇒ ChannelEmitter

Removes the sub-channel from the current channel.

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | channelName | string | the name for the channel |

channel-emitter~emit(eventName, [...args]) ⇒ Boolean

EventEmitter wrapper that emits an event to siblings and direct ancestor channels.

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | eventName | string | the name for the registered event | | [...args] | * | arguments to emit to the event |

channel-emitter~broadcast(eventName, [...args]) ⇒ Boolean

Broadcasts an event to siblings and descendent channels.

Kind: inner method of channel-emitter

| Param | Type | Description | | --- | --- | --- | | eventName | string | the name for the registered event | | [...args] | * | arguments to broadcast to the event |

License

Apache 2.0