How to Add Custom Data to CSV Imports

class TEC_CSV_Import_Custom_Metadata {
	/**
	 * Define your custom data here.
	 * key   => the meta key that will be used to save the data
	 * value => The label of the data used for column mapping
	 *
	 * @var string[]
	 */
	public $custom_import_data = [
		'_tribe_events_status' => 'Event Status',
		'meta_key_1'           => 'Meta Data 1',
		'meta_key_2'           => 'Meta Data 2',
	];

	/**
	 * Constructor.
	 */
	public function __construct() {
		add_filter( 'tribe_events_importer_event_column_names', [ $this, 'add_column_name' ] );

		add_filter( 'tribe_events_csv_import_event_additional_fields', [ $this, 'process_custom_data' ] );

		add_action( 'tribe_events_update_meta', [ $this, 'save_custom_data' ], 10, 3 );
	}

	/**
	 * Add the field name to the dropdown.
	 *
	 * @param array<string|string> $column_names An array of column names for event import.
	 *
	 * @return string[]
	 */
	public function add_column_name( $column_names ) {
		foreach ( $this->custom_import_data as $key => $value ) {
			$column_names[ $key ] = $value;
		}

		return $column_names;
	}

	/**
	 * Make sure that the added column gets processed on import.
	 *
	 * @return array
	 */
	function process_custom_data() {
		// key (meta field name, table column name) => CSV column ID, the key from the above function.
		$extra_fields[ 'tec_import_event_status' ] = 'tec_import_event_status';

		foreach ( $this->custom_import_data as $key => $value ) {
			$extra_fields[ $key ] = $key;
		}

		return $extra_fields;
	}

	/**
	 * Save metadata in database.
	 *
	 * @param int     $event_id The event ID we are modifying meta for.
	 * @param array   $data     The meta fields we want saved.
	 * @param WP_Post $event The event itself.
	 *
	 * @return void
	 */
	function save_custom_data( $event_id, $data, $event ) {
		foreach ( $this->custom_import_data as $key => $value ) {
			if ( isset( $data[ $key ] ) && $data[ $key ] != '' ) {
				update_post_meta( $event_id, $key, esc_html( $data[ $key ] ) );
			}
		}
	}
}

new TEC_CSV_Import_Custom_Metadata();