as noted by mscdex: openBox should use the emptyFn variable instead of creating a new empty function every time when readonly and cb are undefined.

Author: Vytautas Jakutis

imap.js

@@ -404,7 +404,7 @@ ImapConnection.prototype.openBox = function(name, readOnly, cb) {
  this._resetBox();
  if (typeof cb === 'undefined') {
  if(typeof readOnly === 'undefined') {
- cb = function(){};
+ cb = emptyFn;
  } else {
  cb = readOnly;
  }
@@ -1418,4 +1418,4 @@ function pipe(pair, socket) {
  socket.on('close', onclose);
 
  return cleartext;
-}
+}