class EventHandler {
	constructor() {
		this.handlers = {};
	}

	on(event, callback){
		if(this.handlers[event]){
			this.handlers[event].push(callback)
		} else {
			this.handlers[event] = [callback]
		}
	}

	trigger(event){
		if(this.handlers["all"]){
			for (var i = 0; i < this.handlers["all"].length; i++) {
				this.handlers["all"][i](event)
			}
		}
		let event_args = Array.from(arguments)
		event_args.shift()
		if(this.handlers[event]){
			for (var i = 0; i < this.handlers[event].length; i++) {
				this.handlers[event][i](...event_args)
			}
		}
	}
}