fix(utils): define link alias + pluralize (#8070)

What:
 * Fix alias of models that have "compound names": eg "related_product"
 * `deleteCascade` option
 * Package to pluralize english words correctly

integration-tests/modules/__tests__/link-modules/define-link.spec.ts

@@ -1,8 +1,9 @@
 import { medusaIntegrationTestRunner } from "medusa-test-utils"
+
 import CurrencyModule from "@medusajs/currency"
+import { MedusaModule } from "@medusajs/modules-sdk"
 import RegionModule from "@medusajs/region"
 import { defineLink } from "@medusajs/utils"
-import { MedusaModule } from "@medusajs/modules-sdk"
 
 jest.setTimeout(50000)
 
@@ -46,6 +47,7 @@ medusaIntegrationTestRunner({
               args: {
                 methodSuffix: "Currencies",
               },
+              deleteCascade: false,
             },
             {
               serviceName: "region",
@@ -55,6 +57,94 @@ medusaIntegrationTestRunner({
               args: {
                 methodSuffix: "Regions",
               },
+              deleteCascade: false,
+            },
+          ],
+          extends: [
+            {
+              serviceName: "currency",
+              fieldAlias: {
+                region: "region_link.region",
+              },
+              relationship: {
+                serviceName: "currencyCurrencyRegionRegionLink",
+                primaryKey: "currency_code",
+                foreignKey: "code",
+                alias: "region_link",
+                isList: false,
+              },
+            },
+            {
+              serviceName: "region",
+              fieldAlias: {
+                currency: "currency_link.currency",
+              },
+              relationship: {
+                serviceName: "currencyCurrencyRegionRegionLink",
+                primaryKey: "region_id",
+                foreignKey: "id",
+                alias: "currency_link",
+                isList: false,
+              },
+            },
+          ],
+        })
+      })
+
+      it("should flag deleteCascade in the link definition", async () => {
+        const currencyLinks = CurrencyModule.linkable
+        const regionLinks = RegionModule.linkable
+
+        const link = defineLink(
+          {
+            linkable: currencyLinks.currency,
+            deleteCascade: true,
+          },
+          regionLinks.region
+        )
+
+        const linkDefinition = MedusaModule.getCustomLinks()
+          .map((linkDefinition: any) => {
+            const definition = linkDefinition(
+              MedusaModule.getAllJoinerConfigs()
+            )
+            return definition.serviceName === link.serviceName && definition
+          })
+          .filter(Boolean)[0]
+
+        expect(link.serviceName).toEqual("currencyCurrencyRegionRegionLink")
+        expect(linkDefinition).toEqual({
+          serviceName: "currencyCurrencyRegionRegionLink",
+          isLink: true,
+          alias: [
+            {
+              name: ["currency_region"],
+              args: {
+                entity: "LinkCurrencyCurrencyRegionRegion",
+              },
+            },
+          ],
+          primaryKeys: ["id", "currency_code", "region_id"],
+          relationships: [
+            {
+              serviceName: "currency",
+              primaryKey: "code",
+              foreignKey: "currency_code",
+              alias: "currency",
+              args: {
+                methodSuffix: "Currencies",
+              },
+              deleteCascade: true,
+            },
+            {
+              serviceName: "region",
+              primaryKey: "id",
+              foreignKey: "region_id",
+              alias: "region",
+              args: {
+                methodSuffix: "Regions",
+              },
+              deleteCascade: false,
             },
           ],
           extends: [
@@ -128,6 +218,7 @@ medusaIntegrationTestRunner({
               args: {
                 methodSuffix: "Currencies",
               },
+              deleteCascade: false,
             },
             {
               serviceName: "region",
@@ -137,6 +228,7 @@ medusaIntegrationTestRunner({
               args: {
                 methodSuffix: "Regions",
               },
+              deleteCascade: false,
             },
           ],
           extends: [