This generally means that the description regex failed
- I fixed it.
https://commons.wikimedia.org/w/index.php?diff=prev&oldid=133135046
Note that template parameters are case sensitive (except for the first letter)!
https://en.wikipedia.org/wiki/Help:Template#Other_details
So a better Regexp should be:
matches = wt.match( /\|\s*[Dd]escription\s*=/ )
Cheers,
Daniel