[sitecore-jss-proxy] The rewriteRequestPath function ignores query string parameters added in a middleware

packages/sitecore-jss-proxy/src/index.test.ts

@@ -63,6 +63,7 @@ describe('rewriteRequestPath', () => {
         headers: {
           'accept-encoding': 'gzip or whatever',
         },
+        query: {},
       } as unknown) as Request;
 
       const actual = rewriteRequestPath(url, mockRequest, config);
@@ -75,19 +76,37 @@ describe('rewriteRequestPath', () => {
         headers: {
           'accept-encoding': 'gzip or whatever',
         },
+        query: {},
       } as unknown) as Request;
 
       const actual = rewriteRequestPath(url, mockRequest, config);
       expect(actual).to.equal(expected);
     });
+
+    it('should return route prefixed with layout service route and with request query appended', () => {
+      const url = '/about';
+      const expected = '/sitecore/layoutsvc/render/jss?item=%2Fabout&sc_apikey={GUID}&foo=bar';
+
+      const req = ({
+        query: { foo: 'bar' },
+        headers: {
+          'accept-encoding': 'gzip or whatever',
+        },
+      } as unknown) as Request;
+
+      const actual = rewriteRequestPath(url, req, config);
+
+      expect(actual).to.equal(expected);
+    });
+
     describe('when url contains a querystring', () => {
       it('should return route prefixed with layout service route and with querystring appended', () => {
         const url = '/about?sc_camp=123456%2078';
         const expected =
-          '/sitecore/layoutsvc/render/jss?item=%2Fabout&sc_apikey={GUID}&sc_camp=123456%2078';
+          '/sitecore/layoutsvc/render/jss?item=%2Fabout&sc_apikey={GUID}&sc_camp=123456%2078&foo=bar';
 
         const req = ({
-          query: { sc_camp: '123456 78' },
+          query: { sc_camp: '123456 78', foo: 'bar' },
           headers: {
             'accept-encoding': 'gzip or whatever',
           },
@@ -164,6 +183,7 @@ describe('rewriteRequestPath', () => {
           headers: {
             'accept-encoding': 'gzip or whatever',
           },
+          query: {},
         } as unknown) as Request;
 
         const actual = rewriteRequestPath(url, req, qsParamsConfig);

packages/sitecore-jss-proxy/src/index.ts

@@ -384,9 +384,10 @@ export function rewriteRequestPath(
   let finalReqPath = decodedReqPath;
   const qsIndex = finalReqPath.indexOf('?');
   let qs = '';
-  if (qsIndex > -1) {
+  if (qsIndex > -1 || Object.keys(req.query).length) {
     qs = buildQueryString((req as ProxyIncomingMessage).query);
-    finalReqPath = finalReqPath.slice(0, qsIndex);
+    // Splice qs part when url contains that
+    if (qsIndex > -1) finalReqPath = finalReqPath.slice(0, qsIndex);
   }
 
   if (config.qsParams) {

packages/sitecore-jss-proxy/src/test/config.test.ts

@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-unused-vars */
 import { ProxyConfig } from '../ProxyConfig';
 
 const config: ProxyConfig = {