eventpipe.js

function EventPipe() {
}

EventPipe.prototype = {
    _ep_init: function() {
	if (!this._ep_events) {
	    this._ep_events = { };
	    this._maxListeners = 10;
	}
    }, 
    on: function(event, proc, priority) {
	var _l = this.listeners(event);

	if (typeof proc !== 'function') {
	    throw new Error('The event listener MUST be a function. You passed in a ' + typeof proc);
	}

	if (_l.length >= this._maxListeners) {
	    console.error('Error: Too many listeners!! This may be a bug in your code');
	}

	priority = (typeof priority === 'number' ? priority : (priority || 50));
	_l.push({
	    priority: priority, 
	    proc: proc
	});
	_l.sort(function(l, r) {
	    return l.priority - r.priority;
	});

	this.emit('newListener', proc);
	return this;
    }, 
    once: function(event, proc, priority) {
	var _proc;
	_proc = function() {
	    this.removeListener(event, _proc);
	    proc.apply(this, arguments);
	}.bind(this);

	this.on(event, _proc, priority);
	return this;
    }, 
    removeListener: function(event, listener) {
	var _l = this.listeners(event);
	var _x = _l.filter(function(lo) {
	    return lo.proc !== listener;
	});
	_x.unshift(0, _l.length);
	_l.splice.apply(_l, _x);
	return this;
    }, 
    removeAllListeners: function(event) {
	var _l = this.listeners(event);
	_l.splice(0, _l.length);
	return this;
    }, 
    emit: function(event) {
	var _l = this.listeners(event);
	var args = Array.prototype.slice.call(arguments, 1);
	var i, _args;
	for (i = 0; i < _l.length && args !== false; ++i) {
            switch (args.length) {
            case 0:
                _args = _l[i].proc();
                break;
            case 1:
                _args = _l[i].proc(args[0]);
                break;
            case 2:
                _args = _l[i].proc(args[0], args[1]);
                break;
            case 3:
                _args = _l[i].proc(args[0], args[1], args[2]);
                break;
            default:
	        _args = _l[i].proc.apply(this, args);
            }
	    if (typeof _args !== 'undefined') {
		args = _args;
	    }
	}

        if (event === 'error' && i === 0) {
            if (args[0] instanceof Error) {
                throw args[0];
            } else {
                throw new Error("Uncaught, unspecified 'error' event");
            }
        }
	return i > 0;
    }, 
    listeners: function(event) {
	this._ep_init();
	if (!event) {
	    throw new Error("Event is not defined or is falsy");
	}

        var event_listeners = this._ep_events[event];
	if (!event_listeners) {
            this._ep_events[event] = [ ];
            return this._ep_events[event];
	}
	return event_listeners;
    }, 
    setMaxListeners: function(n) {
	this._ep_init();
	this._maxListeners = (Number(n) === NaN ? 10 : Number(n));
	return this;
    }
};

EventPipe.prototype.addListener = EventPipe.prototype.on;

exports.EventPipe = EventPipe;