Testing for non-empty fields, I would have expected simply `if(conference)` or, if there may be whitespace only, `if(conference.trim())`. If there is a different reason, I doubt we'll remember, since this was 2 years ago (https://github.com/zotero/translators/commit/525f2f79c1f52f8bbf403afce54c37af2c00edd4)

Also, interestingly, you have flipped the logic of these tests previously https://github.com/zotero/translators/commit/1d6033739b06a26cd55b28fbb8366d4188aad32d Any idea why?