index.js
//return emitter after adding error listner
return emitter after adding error listner
return emitter after adding error listner
function addErrorListener(emitter, errListener){
  emitter.on(
    'error',
    errListener == undefined || errListener == null ?
    defaultErrorListener :
    errListener
  );
  return emitter;
}
function addErrorListener ( emitter , errListener ) { emitter . on ( 'error' , errListener == undefined || errListener == null ? defaultErrorListener : errListener ) ; return emitter ; }
return emitter after adding error listner
return emitter after adding error listner