WordPress plugin: insert-sub-and-category
I wrote a plugin for WordPress.
You can find a lot of plugins in the WordPress repository, but I couldn't find that one fitting my needs. For this reason, I decided to write my own, and at the same time develop knowledge of how the system works, as well as the practice of writing code in php and js.
I also had to learn more about the default editor - TinyMCE, as I wanted the plugin to work while editing and creating posts, pages and categories. After introducing a new editor (Gutenberg), used in Wordpress above version 5.0 inclusive, the plugin also works, only it's available via shortcode. You can also install a plugin to restore the classic TinyMCE editor :-).
I made the decision to write the plugin at the end of March 2017, when most of the tasks and issues related to creating a template for the Stowarzyszenie Formacja Armum were completed and resolved. At that time, I had an idea and a need for this plugin, although its use and general shape grew up with time. I wanted the plugin to have enough options (not only for basic users).
About the plugin itself - insert-sub-and-category
The insert-sub-and-category plugin is a WordPress plugin that inserts categories and subcategories from your WordPress into posts or categories.
One of its pretty obvious uses is displaying a sitemap, but unlike other solutions - in this case you can limit the displayed results to a specific category (or subcategory).
The plugin adds its own button in the TinyMCE editor, so it's easy to use. If your WordPress version is above 5.0, it is also possible to use it in the Gutenberg editor - via the shortcode insert_sub_and_category. In brief: plugin uses the get_categories function, and a list of all its options can be found in WP_Term_Query::__construct.