Effect: Make .transfer() callback optional

Adds two tests to at least check that no exception is thrown.

Fixes #12223
Closes gh-1545

1 files changed, 3 insertions, 1 deletions

diff --git a/ui/effect.js b/ui/effect.js
index cc9a91045..a946c6e8b 100644
--- a/ui/effect.js
+++ b/ui/effect.js
@@ -1505,7 +1505,9 @@ $.fn.extend({
 				})
 				.animate( animation, options.duration, options.easing, function() {
 					transfer.remove();
-					done();
+					if ( $.isFunction( done ) ) {
+						done();
+					}
 				});
 	}
 });