Adds removeLineItem in CartService with tests

packages/medusa/src/models/__mocks__/cart.js

@@ -143,6 +143,23 @@ export const carts = {
         },
         quantity: 10,
       },
+      {
+        _id: IdMap.getId("itemToRemove"),
+        title: "merge line",
+        description: "This is a new line",
+        thumbnail: "test-img-yeah.com/thumb",
+        content: {
+          unit_price: 123,
+          variant: {
+            _id: IdMap.getId("can-cover"),
+          },
+          product: {
+            _id: IdMap.getId("product"),
+          },
+          quantity: 1,
+        },
+        quantity: 1,
+      },
     ],
     shipping_address: {},
     billing_address: {},

packages/medusa/src/services/__tests__/cart.js

@@ -14,6 +14,7 @@ import { CartModelMock, carts } from "../../models/__mocks__/cart"
 import { LineItemServiceMock } from "../__mocks__/line-item"
 import { DiscountModelMock, discounts } from "../../models/__mocks__/discount"
 import { DiscountServiceMock } from "../__mocks__/discount"
+import idMap from "medusa-test-utils/dist/id-map"
 
 describe("CartService", () => {
   describe("retrieve", () => {
@@ -337,6 +338,75 @@ describe("CartService", () => {
     })
   })
 
+  describe("removeLineItem", () => {
+    const cartService = new CartService({
+      cartModel: CartModelMock,
+      productVariantService: ProductVariantServiceMock,
+      lineItemService: LineItemServiceMock,
+      eventBusService: EventBusServiceMock,
+    })
+
+    beforeEach(() => {
+      jest.clearAllMocks()
+    })
+
+    it("successfully removes a line item", async () => {
+      await cartService.removeLineItem(
+        IdMap.getId("cartWithLine"),
+        IdMap.getId("itemToRemove")
+      )
+
+      expect(EventBusServiceMock.emit).toHaveBeenCalledTimes(1)
+      expect(EventBusServiceMock.emit).toHaveBeenCalledWith(
+        "cart.updated",
+        expect.any(Object)
+      )
+
+      expect(CartModelMock.updateOne).toHaveBeenCalledTimes(1)
+      expect(CartModelMock.updateOne).toHaveBeenCalledWith(
+        {
+          _id: IdMap.getId("cartWithLine"),
+        },
+        {
+          $pull: { items: { _id: IdMap.getId("itemToRemove") } },
+        }
+      )
+    })
+
+    it("successfully decrements quantity if more than 1", async () => {
+      await cartService.removeLineItem(
+        IdMap.getId("cartWithLine"),
+        IdMap.getId("existingLine")
+      )
+
+      expect(EventBusServiceMock.emit).toHaveBeenCalledTimes(1)
+      expect(EventBusServiceMock.emit).toHaveBeenCalledWith(
+        "cart.updated",
+        expect.any(Object)
+      )
+
+      expect(CartModelMock.updateOne).toHaveBeenCalledTimes(1)
+      expect(CartModelMock.updateOne).toHaveBeenCalledWith(
+        {
+          _id: IdMap.getId("cartWithLine"),
+          "items._id": IdMap.getId("existingLine"),
+        },
+        {
+          $set: { "items.$.quantity": 9 },
+        }
+      )
+    })
+
+    it("resolves if line item is not in cart", async () => {
+      await cartService.removeLineItem(
+        IdMap.getId("cartWithLine"),
+        IdMap.getId("nonExisting")
+      )
+
+      expect(CartModelMock.updateOne).toHaveBeenCalledTimes(0)
+    })
+  })
+
   describe("updateLineItem", () => {
     const cartService = new CartService({
       cartModel: CartModelMock,

packages/medusa/src/services/cart.js

@@ -230,6 +230,62 @@ class CartService extends BaseService {
     return c
   }
 
+  /**
+   * Removes a line item from the cart.
+   * @param {string} cartId - the id of the cart that we will remove from
+   * @param {LineItem} lineItemId - the line item to remove.
+   * @retur {Promise} the result of the update operation
+   */
+  async removeLineItem(cartId, lineItemId) {
+    const cart = await this.retrieve(cartId)
+    const itemToRemove = cart.items.find(line => line._id === lineItemId)
+
+    if (!itemToRemove) {
+      return Promise.resolve()
+    }
+
+    // If cart has more than one of those line items, we update the quantity
+    // instead of removing it
+    if (itemToRemove.quantity > 1) {
+      const newQuantity = itemToRemove.quantity - 1
+
+      return this.cartModel_
+        .updateOne(
+          {
+            _id: cartId,
+            "items._id": itemToRemove._id,
+          },
+          {
+            $set: {
+              "items.$.quantity": newQuantity,
+            },
+          }
+        )
+        .then(result => {
+          // Notify subscribers
+          this.eventBus_.emit(CartService.Events.UPDATED, result)
+          return result
+        })
+    }
+
+    return this.cartModel_
+      .updateOne(
+        {
+          _id: cartId,
+        },
+        {
+          $pull: {
+            items: { _id: itemToRemove._id },
+          },
+        }
+      )
+      .then(result => {
+        // Notify subscribers
+        this.eventBus_.emit(CartService.Events.UPDATED, result)
+        return result
+      })
+  }
+
   /**
    * Adds a line item to the cart.
    * @param {string} cartId - the id of the cart that we will add to