chore(medusa): Improve store list products (#3252)

* chore(medusa): Improve list products by 46.5 percents

* fix handler

* todo's

* Create tricky-terms-wash.md

---------

Co-authored-by: Oliver Windall Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/medusa/src/api/routes/store/products/list-products.ts

@@ -11,7 +11,6 @@ import {
   CartService,
   ProductService,
   ProductVariantInventoryService,
-  RegionService,
 } from "../../../../services"
 import SalesChannelFeatureFlag from "../../../../loaders/feature-flags/sales-channels"
 import PricingService from "../../../../services/pricing"
@@ -23,6 +22,7 @@ import { IsType } from "../../../../utils/validators/is-type"
 import { FlagRouter } from "../../../../utils/flag-router"
 import PublishableAPIKeysFeatureFlag from "../../../../loaders/feature-flags/publishable-api-keys"
 import { cleanResponseData } from "../../../../utils/clean-response-data"
+import { Cart, Product } from "../../../../models"
 
 /**
  * @oas [get] /products
@@ -187,15 +187,16 @@ export default async (req, res) => {
     req.scope.resolve("productVariantInventoryService")
   const pricingService: PricingService = req.scope.resolve("pricingService")
   const cartService: CartService = req.scope.resolve("cartService")
-  const regionService: RegionService = req.scope.resolve("regionService")
 
   const validated = req.validatedQuery as StoreGetProductsParams
+
   let {
     cart_id,
     region_id: regionId,
     currency_code: currencyCode,
     ...filterableFields
   } = req.filterableFields
+
   const listConfig = req.listConfig
 
   // get only published products for store endpoint
@@ -212,37 +213,50 @@ export default async (req, res) => {
     }
   }
 
-  const [rawProducts, count] = await productService.listAndCount(
-    filterableFields,
-    listConfig
-  )
+  const promises: Promise<any>[] = []
+
+  promises.push(productService.listAndCount(filterableFields, listConfig))
 
   if (validated.cart_id) {
-    const cart = await cartService.retrieve(validated.cart_id, {
-      select: ["id", "region_id"],
-    })
-    const region = await regionService.retrieve(cart.region_id, {
-      select: ["id", "currency_code"],
-    })
-    regionId = region.id
-    currencyCode = region.currency_code
+    promises.push(
+      cartService.retrieve(validated.cart_id, {
+        select: ["id", "region_id"] as any,
+        relations: ["region"],
+      })
+    )
   }
 
-  const pricedProducts = await pricingService.setProductPrices(rawProducts, {
-    cart_id: cart_id,
-    region_id: regionId,
-    currency_code: currencyCode,
-    customer_id: req.user?.customer_id,
-    include_discount_prices: true,
-  })
+  const [[rawProducts, count], cart] = (await Promise.all(promises)) as [
+    [Product[], number],
+    Cart
+  ]
 
-  const products = await productVariantInventoryService.setProductAvailability(
-    pricedProducts,
-    filterableFields.sales_channel_id
-  )
+  if (validated.cart_id) {
+    regionId = cart.region_id
+    currencyCode = cart.region.currency_code
+  }
+
+  // Create a new reference just for naming purpose
+  const computedProducts = rawProducts
+
+  // We can run them concurrently as the new properties are assigned to the references
+  // of the appropriate entity
+  await Promise.all([
+    pricingService.setProductPrices(computedProducts, {
+      cart_id: cart_id,
+      region_id: regionId,
+      currency_code: currencyCode,
+      customer_id: req.user?.customer_id,
+      include_discount_prices: true,
+    }),
+    productVariantInventoryService.setProductAvailability(
+      computedProducts,
+      filterableFields.sales_channel_id
+    ),
+  ])
 
   res.json({
-    products: cleanResponseData(products, req.allowedProperties || []),
+    products: cleanResponseData(computedProducts, req.allowedProperties || []),
     count,
     offset: validated.offset,
     limit: validated.limit,