Allow API operations to be more customizable

lib/bigcommerce/api/cart/index.ts

@@ -0,0 +1,197 @@
+import { serialize, CookieSerializeOptions } from 'cookie'
+import isAllowedMethod from '../utils/is-allowed-method'
+import createApiHandler, {
+  BigcommerceApiHandler,
+  BigcommerceHandler,
+} from '../utils/create-api-handler'
+import { BigcommerceApiError } from '../utils/errors'
+import getCart from './handlers/get-cart'
+
+type Body<T> = Partial<T> | undefined
+
+export type ItemBody = {
+  productId: number
+  variantId: number
+  quantity?: number
+}
+
+export type AddItemBody = { item: ItemBody }
+
+export type UpdateItemBody = { itemId: string; item: ItemBody }
+
+export type RemoveItemBody = { itemId: string }
+
+// TODO: this type should match:
+// https://developer.bigcommerce.com/api-reference/cart-checkout/server-server-cart-api/cart/getacart#responses
+export type Cart = {
+  id: string
+  parent_id?: string
+  customer_id: number
+  email: string
+  currency: { code: string }
+  tax_included: boolean
+  base_amount: number
+  discount_amount: number
+  cart_amount: number
+  line_items: {
+    custom_items: any[]
+    digital_items: any[]
+    gift_certificates: any[]
+    physical_items: any[]
+  }
+  // TODO: add missing fields
+}
+
+export type CartHandlers = {
+  getCart: BigcommerceHandler<Cart, { cartId?: string }>
+}
+
+const METHODS = ['GET', 'POST', 'PUT', 'DELETE']
+
+// TODO: a complete implementation should have schema validation for `req.body`
+const cartApi: BigcommerceApiHandler<Cart, CartHandlers> = async (
+  req,
+  res,
+  config,
+  handlers
+) => {
+  if (!isAllowedMethod(req, res, METHODS)) return
+
+  const { cookies } = req
+  const cartId = cookies[config.cartCookie]
+
+  try {
+    // Return current cart info
+    if (req.method === 'GET') {
+      return await handlers['getCart']({ req, res, config, body: { cartId } })
+    }
+
+    // Create or add an item to the cart
+    if (req.method === 'POST') {
+      const { item } = (req.body as Body<AddItemBody>) ?? {}
+
+      if (!item) {
+        return res.status(400).json({
+          data: null,
+          errors: [{ message: 'Missing item' }],
+        })
+      }
+      if (!item.quantity) item.quantity = 1
+
+      const options = {
+        method: 'POST',
+        body: JSON.stringify({
+          line_items: [parseItem(item)],
+        }),
+      }
+      const { data } = cartId
+        ? await config.storeApiFetch(`/v3/carts/${cartId}/items`, options)
+        : await config.storeApiFetch('/v3/carts', options)
+
+      // Create or update the cart cookie
+      res.setHeader(
+        'Set-Cookie',
+        getCartCookie(config.cartCookie, data.id, config.cartCookieMaxAge)
+      )
+
+      return res.status(200).json({ data })
+    }
+
+    // Update item in cart
+    if (req.method === 'PUT') {
+      const { itemId, item } = (req.body as Body<UpdateItemBody>) ?? {}
+
+      if (!cartId || !itemId || !item) {
+        return res.status(400).json({
+          data: null,
+          errors: [{ message: 'Invalid request' }],
+        })
+      }
+
+      const { data } = await config.storeApiFetch(
+        `/v3/carts/${cartId}/items/${itemId}`,
+        {
+          method: 'PUT',
+          body: JSON.stringify({
+            line_item: parseItem(item),
+          }),
+        }
+      )
+
+      // Update the cart cookie
+      res.setHeader(
+        'Set-Cookie',
+        getCartCookie(config.cartCookie, cartId, config.cartCookieMaxAge)
+      )
+
+      return res.status(200).json({ data })
+    }
+
+    // Remove an item from the cart
+    if (req.method === 'DELETE') {
+      const { itemId } = (req.body as Body<RemoveItemBody>) ?? {}
+
+      if (!cartId || !itemId) {
+        return res.status(400).json({
+          data: null,
+          errors: [{ message: 'Invalid request' }],
+        })
+      }
+
+      const result = await config.storeApiFetch<{ data: any } | null>(
+        `/v3/carts/${cartId}/items/${itemId}`,
+        { method: 'DELETE' }
+      )
+      const data = result?.data ?? null
+
+      res.setHeader(
+        'Set-Cookie',
+        data
+          ? // Update the cart cookie
+            getCartCookie(config.cartCookie, cartId, config.cartCookieMaxAge)
+          : // Remove the cart cookie if the cart was removed (empty items)
+            getCartCookie(config.cartCookie)
+      )
+
+      return res.status(200).json({ data })
+    }
+  } catch (error) {
+    console.error(error)
+
+    const message =
+      error instanceof BigcommerceApiError
+        ? 'An unexpected error ocurred with the Bigcommerce API'
+        : 'An unexpected error ocurred'
+
+    res.status(500).json({ data: null, errors: [{ message }] })
+  }
+}
+
+function getCartCookie(name: string, cartId?: string, maxAge?: number) {
+  const options: CookieSerializeOptions =
+    cartId && maxAge
+      ? {
+          maxAge,
+          expires: new Date(Date.now() + maxAge * 1000),
+          secure: process.env.NODE_ENV === 'production',
+          path: '/',
+          sameSite: 'lax',
+        }
+      : { maxAge: -1, path: '/' } // Removes the cookie
+
+  return serialize(name, cartId || '', options)
+}
+
+const parseItem = (item: ItemBody) => ({
+  quantity: item.quantity,
+  product_id: item.productId,
+  variant_id: item.variantId,
+})
+
+const handlers = {
+  getCart,
+}
+
+const h = createApiHandler(cartApi, handlers)
+
+export default h