Fix crash when converting bundles without entries to R4

tests/tx/search.test.js

@@ -236,6 +236,32 @@ describe('Search Worker', () => {
       expect(response.body.link).toBeUndefined();
     });
 
+    test('should return only count with _summary=count for ValueSet', async () => {
+      const response = await request(app)
+        .get('/tx/r5/ValueSet')
+        .query({ _summary: 'count' })
+        .set('Accept', 'application/json');
+
+      expect(response.status).toBe(200);
+      expect(response.body.resourceType).toBe('Bundle');
+      expect(response.body.type).toBe('searchset');
+      expect(response.body.total).toBeGreaterThan(0);
+      expect(response.body.entry).toBeUndefined();
+    });
+
+    test('bundleFromR5 handles bundle without entries', () => {
+      const { bundleFromR5 } = require('../../tx/xversion/xv-bundle');
+      const r5Bundle = {
+        resourceType: 'Bundle',
+        type: 'searchset',
+        total: 42
+      };
+      const r4Bundle = bundleFromR5(r5Bundle, '4.0.1');
+      expect(r4Bundle.resourceType).toBe('Bundle');
+      expect(r4Bundle.total).toBe(42);
+      expect(r4Bundle.entry).toBeUndefined();
+    });
+
     test('should return full resources with _summary=false', async () => {
       const response = await request(app)
         .get('/tx/r5/CodeSystem')

tx/xversion/xv-bundle.js

@@ -15,7 +15,7 @@ function bundleToR5(jsonObj, sourceVersion) {
     return jsonObj; // No conversion needed
   }
 
-  for (let be of jsonObj.entry) {
+  for (let be of jsonObj.entry || []) {
     convertResourceToR5(be.resource, sourceVersion);
   }
 
@@ -51,7 +51,7 @@ function bundleFromR5(r5Obj, targetVersion) {
   }
   bundle.total = r5Obj.total;
   bundle.link = r5Obj.link;
-  for (let be5 of r5Obj.entry) {
+  for (let be5 of r5Obj.entry || []) {
     let be = {};
     if (!bundle.entry) {
       bundle.entry = [];
@@ -68,4 +68,4 @@ function bundleFromR5(r5Obj, targetVersion) {
   return bundle;
 }
 
-module.exports = { bundleToR5, bundleFromR5 };
+module.exports = { bundleToR5, bundleFromR5 };