event emitters from the CJS2014 talk

ee.js

var ee = createEE()

ee.emit('foo', [1, 2, 3])

ee.on('bar', function (a, b, c) {
	console.log('bar: ' + a);
	return b;
});

console.log('emit returned: ' + ee.emit('bar', [1, 2, 3]));

function createEE() {
	var events = {};

	function on (type, handler) {
		events[type] = listeners(type).concat(handler);
	}
	
	function off (type, handler) {
		var fns = listeners(type);
		
		events[type] = fns.splice(fns.indexOf(handlers), 1)
	}

	function listeners (type) {
		return events[type] || []
	}

	function emit (type, args) {
		var self = this,
			fns = listeners(type);
		
		return fns.map(function (fn) {
			return fn.apply(self, args)
		});
	}

	return {
		"on": on,
		"off": off,
		"emit": emit,
		"listeners": listeners,
		"events": events
	}

}