Custom Fields API

Register your own metadata fields on references. Registered fields integrate with the reference admin UI, the REST API (optional), and export.

Register a field

Call ABT_Custom_Fields::register_field() with a field ID and arguments, typically on init:

add_action( 'init', function () {
    ABT_Custom_Fields::register_field( 'custom_rating', array(
        'label'        => 'Rating',
        'type'         => 'number',
        'description'  => 'Rate this reference 1-5',
        'min'          => 1,
        'max'          => 5,
        'show_in_rest' => true,
    ) );
} );

Arguments

Key	Default	Description
label	(from field ID)	Field label in the admin
type	text	Field type: text, number, select, and other supported types
description	(empty)	Help text shown under the field
default	(empty)	Default value
options	[]	Choices for select / radio field types
sanitize	(by type)	Sanitize callback; defaults to one appropriate for the type
show_in_rest	false	Expose the field in the REST API
show_in_admin	true	Show the field on the reference edit screen
show_in_export	true	Include the field when exporting

If you omit label, it is generated from the field ID. If you omit sanitize, a default callback is chosen based on type. Unknown types fall back to text.

Unregister a field

ABT_Custom_Fields::unregister_field( 'custom_rating' );