Create alt date post meta ( timestamp )

Create alt date post meta ( timestamp )

add_action( 'save_post_event', '__your_prefix__save_event_start_date_timestamp', 10, 3 );

function __your_prefix__save_event_start_date_timestamp( $post_id, $post, $update ) {

	if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
		return;
	}

	$event_start_date = $_POST[ 'event_start_date' ];

	if ( empty( $event_start_date ) ) {
		return;
	}

	$event_start_date_timestamp = date_i18n( 'U', strtotime( $event_start_date ) );

	update_post_meta( $post_id, '_je_event_start_date_timestamp', $event_start_date_timestamp );
}