Use global value to check for current Shop product

Also add other stores types to hint on expected values

src/utils/stores/shop.ts

@@ -1,14 +1,20 @@
-import { writable, derived } from 'svelte/store'
+import { writable, derived, type Writable, type Readable } from 'svelte/store'
+
+
+/**
+ * Shop
+ */
+export const shopCurrentProductSlug: Writable<string> = writable(null)
 
 
 /**
  * Cart
  */
 /** Cart open state */
-export const cartOpen = writable(false)
+export const cartOpen: Writable<boolean> = writable(false)
 
 /** Cart open state */
-export const cartId = writable(null)
+export const cartId: Writable<string> = writable(null)
 
 // Write to localStorage when changing cartId
 if (typeof localStorage !== 'undefined') {
@@ -20,17 +26,18 @@ if (typeof localStorage !== 'undefined') {
 }
 
 /** Raw Cart data */
-export const cartData = writable(null)
+export const cartData: Writable<any> = writable(null)
 
 /** Cart data is being updated */
-export const cartIsUpdating = writable(false)
+export const cartIsUpdating: Writable<boolean> = writable(false)
 
 /** Amount of products present in cart */
-export const cartAmount = derived(cartData, ($cart) => {
+export const cartAmount: Readable<number> = derived(cartData, ($cart) => {
     return $cart && $cart.item_quantity > 0 ? $cart.item_quantity : 0
 })
 
+
 /**
  * Notifications
  */
-export const cartNotifications = writable([])
+export const cartNotifications: Writable<any[]> = writable([])