diff --git a/share/server/dispatch-quickjs.js b/share/server/dispatch-quickjs.js
index 5f69f6188ac..2f05118b313 100644
--- a/share/server/dispatch-quickjs.js
+++ b/share/server/dispatch-quickjs.js
@@ -154,7 +154,8 @@ globalThis.dispatch = function(line) {
   const cmd = JSON.parse(line);
   State.line_length = line.length;
   try {
-    switch (cmd.shift()) {
+    const cmdkey = cmd.shift();
+    switch (cmdkey) {
     case "ddoc":
       DDoc.ddoc.apply(null, cmd);
       break;
diff --git a/src/couch/test/eunit/couch_js_tests.erl b/src/couch/test/eunit/couch_js_tests.erl
index 29b303ffb5f..c5ad53eaaaf 100644
--- a/src/couch/test/eunit/couch_js_tests.erl
+++ b/src/couch/test/eunit/couch_js_tests.erl
@@ -38,7 +38,8 @@ couch_js_test_() ->
                 ?TDEF(should_allow_js_string_mutations),
                 ?TDEF(should_bump_timing_and_call_stats),
                 ?TDEF(should_exit_on_internal_error, 60),
-                ?TDEF(should_use_bigint)
+                ?TDEF(should_use_bigint),
+                ?TDEF(should_handle_invalid_command)
             ])
         }
     }.
@@ -465,6 +466,11 @@ should_use_bigint(_) ->
             ?assertThrow({compilation_error, _}, prompt(Proc, [<<"add_fun">>, Src]))
     end.
 
+should_handle_invalid_command(_) ->
+    Proc = couch_query_servers:get_os_process(<<"javascript">>),
+    BadCmd = [<<"bad">>, <<"foo">>],
+    ?assertThrow({unknown_command, <<"unknown command 'bad'">>}, prompt(Proc, BadCmd)).
+
 sample_time(Stat) ->
     couch_stats:sample([couchdb, query_server, time, Stat]).