Added op to get the logged in customer

lib/bigcommerce/api/customers/handlers/get-logged-in-customer.ts

@@ -0,0 +1,44 @@
+import { GetLoggedInCustomerQuery } from '@lib/bigcommerce/schema'
+import type { CustomersHandlers } from '..'
+
+export const getLoggedInCustomerQuery = /* GraphQL */ `
+  query getLoggedInCustomer {
+    customer {
+      entityId
+      firstName
+      lastName
+      email
+      company
+      customerGroupId
+      notes
+      phone
+      addressCount
+      attributeCount
+      storeCredit {
+        value
+        currencyCode
+      }
+    }
+  }
+`
+
+const getLoggedInCustomer: CustomersHandlers['getLoggedInCustomer'] = async ({
+  res,
+  config,
+}) => {
+  const data = await config.fetch<GetLoggedInCustomerQuery>(
+    getLoggedInCustomerQuery
+  )
+  const { customer } = data
+
+  if (!customer) {
+    return res.status(400).json({
+      data: null,
+      errors: [{ message: 'Customer not found', code: 'not_found' }],
+    })
+  }
+
+  res.status(200).json({ data: { customer } })
+}
+
+export default getLoggedInCustomer