Event manager and Callback Manager

callback.js

class Callbacks{
	constructor(){
		this.cb = {};
	}

	on( eName, func ){ 
		if( !this.cb[ eName ] ) this.cb[ eName ] = new Array();
		this.cb[ eName ].push( func );
		return this;
	}
	
	off( eName, func ){ 
		let idx = this.cb[ eName ].indexOf( func );
		if( idx !== -1 ) this.cb[ eName ].splice( idx, 1 );

		return this;
	}
	
	offAll( eName ){
		let ary = this.cb[ eName ];
		
		if( !ary ) 	console.error( "Callbacks.offAll : Event Name Not Found ", eName );
		else 		ary.length = 0;

		return this;
	}

	count( eName ){ return ( this.cb[ eName ] )? this.cb[ eName ].length : 0; }
	
	// emit( name, detail)
	emit( eName, data=null ){
		if( this.count( eName ) ){
			let f;
			for( f of this.cb[ eName ] ){
				try{
					f( data );
				}catch( err ){
					console.error("Callback.emit ", eName, " : ", err );
				}
			}
		}
		return this;
	}

}

export default Callbacks;

event_man.js

class EventManager{
	constructor(){ 
		this.elm	= document.createElement("i");
		this.events	= {};
	}

	on( eName, func ){ 
		this.elm.addEventListener( eName, func );
		if( !this.events[ eName ] ) this.events[ eName ] = new Array();
		this.events[ eName ].push( func );
		return this;
	}

	off( eName, func ){ 
		this.elm.removeEventListener( eName, func );
		let idx = this.events[ eName ].indexOf( func );
		if( idx !== -1 ) this.events[ eName ].splice( idx, 1 );
		return this;
	}

	off_all( eName ){
		let ary = this.events[ eName ];
		if( !ary ) console.error( "EventManager.off_all : Event Name Not Found ", eName );
		else{
			let func;
			for( func of ary ) this.elm.removeEventListener( eName, func );
		}
		return this;
	}

	emit( eName, detail=null ){ 
		this.elm.dispatchEvent( new CustomEvent( eName, { detail, bubbles:true, cancelable:true, composed:false } ) ); 
		return this;
	}
}
export default EventManager;