ee.js

It's not that the world needs yet another JavaScript event emitter, but they are fun to write, and this one comes with a few differentiating features. It's also works without any dependency on the browser or other libraries.

• Handlers can be turned off by name, fn, or both.
• Duplicate handlers with the same name and fn are ignored.
• Handlers added with once or times will not cause infinite loops.
• Each emitter method returns the emitter to allow chaining.

Eexample

var e = ee();

e.on('hello', function() { console.log('world'); })
 .on('world', function() { console.log('hello'); })
 .on('world', function() { console.log('earth'); })
 .once('foo', function() { console.log('bar'); });

e.emit('hello')  // => 'world'
 .emit('world'); // => 'hello', 'earth'

e.off('hello')
 .has('world');  // => 2

e.emit('foo')    // => 'bar'
 .has('foo');    // => 0

API

ee([obj])

ee creates a new emitter object, or extends an existing object with emitter methods.

.on(name, func, [context], [args...])

.on adds a new handler which will be fired when its name is emitted. You may optionally specify the context for the handler, and any arguments which should be applied when the handler is called.

.once(name, [context], [args...])

.once adds a new handler which will be removed after it has been called.

.times(n, name, [context], [args...])

.times adds a new handler which will be removed after it has been called n times.

.emit(name, [context], [args...])

.emit fires all handlers registered for this event. You may optionally specify the context for the handler, and any arguments which should be applied when the handler is called.

.has([name], [fn])

.has checks if there's a registered handler for an event name, and returns the number of registered handlers for this event. Pass a function to see if the emitter has that function as a registered this specific handler for the event. Call .has without any arguments to get the total number of registered handlers.

.off([name], [fn])

.off removes a handler by name, or by name and function. Call .off without any arguments to remove all handlers.

License

MIT. See LICENSE.