detect/capture if items bought or sold in shop

Hi Everyone,

May i ask some help, I'm building a custom javascript functions to call when something bought or sold in a shop, my goal is to trigger a javascript function and pass the item variables when the player bought or sold something in shop.

Code:

//list items in a varialble ["ItemType","ID","CustomPrice","CustomPriceValue"]
var goods = [
   [ 0, 12, 1, 400 ],//potion
   [ 2, 30, 1, 800 ]//superpotion
]
//then i use scenemanager to list the goods inside the shop
SceneManager.push(Scene_Shop);
SceneManager.prepareNextScene(goods, false);

whenever the player bought or sold it will trigger the functions i created to capture what item is it (pass variables) and do some procedures.

//this function will trigger when they buy something in shop

Code:

boughtItem("ItemType","ID","CustomPrice","CustomPriceValue")

//this function will trigger when they sell something in shop

Code:

soldItem("ItemType","ID","CustomPrice","CustomPriceValue")

Can somebody here can help me please how to trigger function or call a script when something is bought or sold in shop. I'm still new in RRMV and need to learn more thanks.