Chore: Updated resolvers from Class to ResolveFn

overlord/src/app/purchase/purchase.resolver.ts

@@ -0,0 +1,13 @@
+import { inject } from '@angular/core';
+import { ResolveFn } from '@angular/router';
+
+import { Voucher } from '../core/voucher';
+import { VoucherService } from '../core/voucher.service';
+
+export const purchaseResolver: ResolveFn<Voucher> = (route) => {
+  const id = route.paramMap.get('id');
+  if (id === null) {
+    return inject(VoucherService).getOfType('Purchase');
+  }
+  return inject(VoucherService).get(id, 'Purchase');
+};