I am trying to use the Javascript API to do some batch editing of item fields. I have a few questions (some of which happen to be long to-dos on the API documentation, so I apologize if they are too complicated to answer here):

1. What are the available search operators for Zotero searches? Specifically, how do I search for "is not"?

2. How do I combine multiple conditions within a search (A & B or A | B)?

3. Is it possible to search for empty fields? What is the value to specify to do so?

Thank you!