feat: enforce SKU validity, use SKU as handle

This commit enforces proper SKU validation, uses the SKU as the Shopify handle, and implements ID-based product updates to allow renaming. It also extracts the IShop interface for TDD.

src/shopifyApi.ts

@@ -18,6 +18,7 @@
 import { Config } from "./config"
 import * as shopify from "shopify-admin-api-typings"
 import gql from 'graphql-tag'
+import { IShop } from "./interfaces/IShop"
 
 const ss = SpreadsheetApp.getActive()
 
@@ -392,7 +393,7 @@ function parseLinkHeader(header) {
   return rels
 }
 
-export class Shop {
+export class Shop implements IShop {
   private shopifyApiKey: string
   private shopifyApiSecretKey: string
   private shopifyAdminApiAccessToken: string
@@ -599,6 +600,34 @@ export class Shop {
     return product
   }
 
+  GetProductById(id: string) {
+    console.log("GetProductById('" + id + "')")
+    let gql = /* GraphQL */ `
+      query productById {
+        product(id: "${id}") {
+          id
+          title
+          handle
+          variants(first: 1) {
+            nodes {
+              id
+              sku
+            }
+          }
+        }
+      }
+    `
+    let query = buildGqlQuery(gql, {})
+    let response = this.shopifyGraphQLAPI(query)
+    if (!response.content.data.product) {
+        console.log("GetProductById: no product matched")
+        return null;
+    }
+    let product = response.content.data.product
+    console.log("Product found:\n" + JSON.stringify(product, null, 2))
+    return product
+  }
+
   GetInventoryItemBySku(sku: string) {
     console.log('GetInventoryItemBySku("' + sku + '")')
     let gql = /* GraphQL */ `
@@ -1132,6 +1161,7 @@ export class ShopifyProductSetQuery {
 export class ShopifyProductSetInput {
   category: string
   descriptionHtml: string
+  handle: string
   id?: string
   productType: string
   redirectNewHandle: boolean = true