pub-sub

A small library that implements pub/sub in JavaScript.

npm install pub-sub
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pub-sub.js

A tiny library that implements pub/sub in JavaScript.

Build status

Installation

Via NPM

npm install pub-sub

Via Jam

jam install pub-sub

Via Git

git clone git@github.com:philbooth/pub-sub.js.git

Usage

Loading the library

Both CommonJS (e.g. if you're running on Node.js or in the browser with Browserify) and AMD (e.g. if you're using Require.js) loading styles are supported. If neither system is detected, the library defaults to exporting it's interface globally as pubsub.

Calling the exported functions

The library exports two functions, createEvent and getEventBroker. Event objects returned by createEvent expose three methods: getName, getData and respond. Event broker objects returned by getEventBroker expose three methods: subscribe, unsubscribe and publish.

createEvent (args)

Returns an event object that can be published via the event broker. args must be an object with a required name property, name being a string used to identify the event. The args object may also contain two optional properties: data, which can be of any type, and callback which must be a function if specified.

event.getName ()

Returns the event name that was specified in the call to createEvent.

event.getData ()

Returns the data property that may optionally have been specified in the call to createEvent.

event.respond (...)

Calls the callback function that may optionally have been specified in the call to createEvent.

getEventBroker (id)

Returns an event broker object that can be used to subscribe to and publish events. The id argument is a string that identifies the event broker, enabling callers to easily access the same event broker from different parts of the code if they so wish.

eventBroker.subscribe (args)

Subscribe to an event. args is an object with two required properties: name, a string identifying the event to subscribe to; and callback, a function that will be called when that event occurs. If the name propery is '*', the supplied callback function will be subscribed to every event that occurs, regardless of event name.

eventBroker.unsubscribe (args)

Unsubscribe a previously subscribed callback. The args object is the same format as was passed to subscribe.

eventBroker.publish (event)

Publish an event to subscribers. event is an object returned by the createEvent function.

Development

Dependencies

The build environment relies on Node.js, NPM, Jake, Mocha, Chai and Spooks.js. Assuming that you already have Node.js and NPM set up, you just need to run npm install to install all of the dependencies as listed in package.json.

Unit tests

The unit tests are in test/pub-sub.js. You can run them with the command npm test or jake test.

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