feat(server): wip tax rate on sale invoice service

packages/server/src/services/TaxRates/ItemEntriesTaxTransactions.ts

@@ -0,0 +1,22 @@
+import { ItemEntry } from "@/models";
+import { sumBy } from "lodash";
+import { Service } from "typedi";
+
+
+@Service()
+export class ItemEntriesTaxTransactions {
+  /**
+   * 
+   * @param model 
+   * @returns 
+   */
+  public assocTaxAmountWithheldFromEntries(model: any) {
+    const entries = model.entries.map((entry) => ItemEntry.fromJson(entry));
+    const taxAmountWithheld = sumBy(entries, 'taxAmount');
+
+    if (taxAmountWithheld) {
+      model.taxAmountWithheld = taxAmountWithheld;
+    }
+    return model;
+  }
+}