opensourcepos/app/Libraries/Item_lib.php

<?php

namespace app\Libraries;

use CodeIgniter\Session\Session;
use app\Models\Stock_location;

/**
 * Item library
 *
 * Library with utilities to manage items
 *
 * @property session session
 * @property stock_location stock_location
 */

class Item_lib
{
  	public function __construct()
	{
		$this->session = Session();
		$this->stock_location = model('Stock_location');
	}

	public function get_item_location(): string
	{
		if(!$this->session->get('item_location'))
		{
			$location_id = $this->stock_location->get_default_location_id();
			$this->set_item_location($location_id);
		}

		return $this->session->get('item_location');
	}

	public function set_item_location(string $location): void
	{
		$this->session->set('item_location',$location);
	}

	public function clear_item_location(): void	//TODO: This isn't called from anywhere in the code.
	{
		$this->session->remove('item_location');
	}
}