feat: Line Items API Routes (#6478)

**What**
- `POST /store/carts/:id/line-items`
- `POST /store/carts/:id/line-items/:id`
- `DELETE /store/carts/:id/line-items/:id`

**Outstanding**
- Integration tests
- Module integrations: Payment, Fulfillment, Promotions

Depends on #6475 and #6449.

packages/medusa/src/api-v2/store/carts/[id]/line-items/[line_id]/route.ts

@@ -0,0 +1,84 @@
+import {
+  deleteLineItemsWorkflow,
+  updateLineItemInCartWorkflow,
+} from "@medusajs/core-flows"
+import { ModuleRegistrationName } from "@medusajs/modules-sdk"
+import { ICartModuleService } from "@medusajs/types"
+import { MedusaError, remoteQueryObjectFromString } from "@medusajs/utils"
+import { MedusaRequest, MedusaResponse } from "../../../../../../types/routing"
+import { defaultStoreCartFields } from "../../../query-config"
+import { StorePostCartsCartLineItemsItemReq } from "./validators"
+
+export const POST = async (req: MedusaRequest, res: MedusaResponse) => {
+  const cartModuleService = req.scope.resolve<ICartModuleService>(
+    ModuleRegistrationName.CART
+  )
+
+  const cart = await cartModuleService.retrieve(req.params.id, {
+    select: ["id", "region_id", "currency_code"],
+    relations: ["region", "items", "items.variant_id"],
+  })
+
+  const item = cart.items?.find((i) => i.id === req.params.line_id)
+
+  if (!item) {
+    throw new MedusaError(
+      MedusaError.Types.NOT_FOUND,
+      `Line item with id: ${req.params.line_id} was not found`
+    )
+  }
+
+  const input = {
+    cart,
+    item,
+    update: req.validatedBody as StorePostCartsCartLineItemsItemReq,
+  }
+
+  const { errors } = await updateLineItemInCartWorkflow(req.scope).run({
+    input,
+    throwOnError: false,
+  })
+
+  if (Array.isArray(errors) && errors[0]) {
+    throw errors[0].error
+  }
+
+  const remoteQuery = req.scope.resolve("remoteQuery")
+
+  const query = remoteQueryObjectFromString({
+    entryPoint: "cart",
+    fields: defaultStoreCartFields,
+  })
+
+  const [updatedCart] = await remoteQuery(query, {
+    cart: { id: req.params.id },
+  })
+
+  res.status(200).json({ cart: updatedCart })
+}
+
+export const DELETE = async (req: MedusaRequest, res: MedusaResponse) => {
+  const id = req.params.line_id
+
+  const { errors } = await deleteLineItemsWorkflow(req.scope).run({
+    input: { ids: [id] },
+    throwOnError: false,
+  })
+
+  if (Array.isArray(errors) && errors[0]) {
+    throw errors[0].error
+  }
+
+  const remoteQuery = req.scope.resolve("remoteQuery")
+
+  const query = remoteQueryObjectFromString({
+    entryPoint: "cart",
+    fields: defaultStoreCartFields,
+  })
+
+  const [cart] = await remoteQuery(query, {
+    cart: { id: req.params.id },
+  })
+
+  res.status(200).json({ cart })
+}

packages/medusa/src/api-v2/store/carts/[id]/line-items/[line_id]/validators.ts

@@ -0,0 +1,9 @@
+import { IsInt, IsOptional } from "class-validator"
+
+export class StorePostCartsCartLineItemsItemReq {
+  @IsInt()
+  quantity: number
+
+  @IsOptional()
+  metadata?: Record<string, unknown> | undefined
+}

packages/medusa/src/api-v2/store/carts/middlewares.ts

@@ -1,6 +1,7 @@
 import { transformBody, transformQuery } from "../../../api/middlewares"
 import { MiddlewareRoute } from "../../../loaders/helpers/routing/types"
 import { authenticate } from "../../../utils/authenticate-middleware"
+import { StorePostCartsCartLineItemsItemReq } from "./[id]/line-items/[line_id]/validators"
 import { StorePostCartsCartLineItemsReq } from "./[id]/line-items/validators"
 import * as QueryConfig from "./query-config"
 import {
@@ -48,6 +49,14 @@ export const storeCartRoutesMiddlewares: MiddlewareRoute[] = [
   },
   {
     method: ["POST"],
+    matcher: "/store/carts/:id/line-items/:line_id",
+    middlewares: [transformBody(StorePostCartsCartLineItemsItemReq)],
+  },
+  {
+    method: ["DELETE"],
+    matcher: "/store/carts/:id/line-items/:line_id",
+  },
+  {
     matcher: "/store/carts/:id/promotions",
     middlewares: [transformBody(StorePostCartsCartPromotionsReq)],
   },