Populate choices from a property that returns an array.

gppa-populate-choices-with-array.php

<?php
/**
 * See https://gravitywiz.com/documentation/how-do-i-install-a-snippet/ for details on how to install snippets like these.
 *
 * The following snippet allows you to use an array to populate the field choices.
 *
 * This will use whatever property is selected in the "Value Template" for the choices.
 *
 * FORMID is the form that the field with dynamically populated choices is on
 * FIELDID is the field ID of the field that you wish to modify the choices for
 */
add_filter( 'gppa_input_choices_FORMID_FIELDID', function ( $choices, $field, $objects ) {
	$choices     = array();
	$object_type = gp_populate_anything()->get_object_type( rgar( $field, 'gppa-choices-object-type' ) );
	$templates   = rgar( $field, 'gppa-choices-templates', array() );

	foreach ( $objects as $object ) {
		$array = $object_type->get_object_prop_value( $object, rgar( $templates, 'value' ) );

		foreach ( $array as $array_item ) {
			$choices[] = array(
				'value' => $array_item,
				'text'  => $array_item,
			);
		}
	}

	return $choices;
}, 10, 3 );