epub.js/fpjs/render/events.js

FP.Events = function(obj, el){
	
	this.events = {};
	
	if(!el){
		this.el = document.createElement('div');
	}else{
		this.el = el;
	}
	
	obj.createEvent = this.createEvent;
	obj.tell = this.tell;
	obj.listen = this.listen;
	obj.deafen = this.deafen;
	obj.listenUntil = this.listenUntil;
	
	return this;
}

FP.Events.prototype.createEvent = function(evt){
	var e = new CustomEvent(evt);
	this.events[evt] = e;
	return e;
}

FP.Events.prototype.tell = function(evt, msg){
	var e;

	if(!this.events[evt]){
		console.warn("No event:", evt,  "defined yet, creating.");
		e = this.createEvent(evt)
	}else{
		e = this.events[evt];
	}

	if(msg) e.msg = msg;

	this.el.dispatchEvent(e);

}

FP.Events.prototype.listen = function(evt, func, bindto){
	if(!this.events[evt]){
		console.warn("No event:", evt,  "defined yet, creating.");
		this.createEvent(evt);
		return;
	}

	if(bindto){
		this.el.addEventListener(evt, func.bind(bindto), false);
	}else{
		this.el.addEventListener(evt, func, false);
	}

}

FP.Events.prototype.deafen = function(evt, func){
	this.el.removeEventListener(evt, func, false);
}

FP.Events.prototype.listenUntil = function(OnEvt, OffEvt, func, bindto){
	this.listen(OnEvt, func, bindto);
	
	function unlisten(){
		this.deafen(OnEvt, func);
		this.deafen(OffEvt, unlisten);
	}
	
	this.listen(OffEvt, unlisten);
}