fix(router): fix redirect to a URL with a param having multiple values (#16376)

fixes #16310

PR Close #16376

packages/router/src/apply_redirects.ts

@@ -358,7 +358,13 @@ class ApplyRedirects {
   private createQueryParams(redirectToParams: Params, actualParams: Params): Params {
     const res: Params = {};
     forEach(redirectToParams, (v: any, k: string) => {
-      res[k] = v.startsWith(':') ? actualParams[v.substring(1)] : v;
+      const copySourceValue = typeof v === 'string' && v.startsWith(':');
+      if (copySourceValue) {
+        const sourceName = v.substring(1);
+        res[k] = actualParams[sourceName];
+      } else {
+        res[k] = v;
+      }
     });
     return res;
   }

packages/router/test/apply_redirects.spec.ts

@@ -41,6 +41,17 @@ describe('applyRedirects', () => {
         (t: UrlTree) => { expectTreeToBe(t, '/a/b/c'); });
   });
 
+  it('should support redirecting with to an URL with query parameters', () => {
+    const config: Routes = [
+      {path: 'single_value', redirectTo: '/dst?k=v1'},
+      {path: 'multiple_values', redirectTo: '/dst?k=v1&k=v2'},
+      {path: '**', component: ComponentA},
+    ];
+
+    checkRedirect(config, 'single_value', (t: UrlTree) => expectTreeToBe(t, '/dst?k=v1'));
+    checkRedirect(config, 'multiple_values', (t: UrlTree) => expectTreeToBe(t, '/dst?k=v1&k=v2'));
+  });
+
   it('should handle positional parameters', () => {
     checkRedirect(
         [