You can add functionality get_usermeta ?

I would like get_usermeta from wp_usermeta for my application.

In my application, my users add some posts in their list of favorite posts.
But the posts are favorites are stored in wp_usermeta.

You have the option of adding a get_usermeta function, which takes as a parameter the fields user_id, meta_key, and return the value ?

cordially

https://wordpress.org/plugins/json-rest-api/