The categories are already set on your WP site as numbers.
Post to them like this when using the Wordpresslib module...
post.categories = ["4"]
There's not much in the documentation of this old Wordpresslib module on how to post to a specific category. Looking through the code of the module itself shows lots of category related classes in it.
('World' is a category already set on the WP site I'm posting to.) I've tried these below but everytime the category of the post on WP is "Uncategorized"...
post.setPostCategories = ["World"] post.categories = ["World"] post.WordPressCategory = ["World"]
Not sure if this involves keys or something or if I'll have to import another module to set the category.