diff --git a/lib/jsonld.js b/lib/jsonld.js
index b420e42d..ef178585 100644
--- a/lib/jsonld.js
+++ b/lib/jsonld.js
@@ -1040,12 +1040,12 @@ function _setDefaults(options, {
   ...defaults
 }) {
   // fail if obsolete options present
-  if(options && 'compactionMap' in options) {
+  if(options?.compactionMap !== undefined) {
     throw new JsonLdError(
       '"compactionMap" not supported.',
       'jsonld.OptionsError');
   }
-  if(options && 'expansionMap' in options) {
+  if(options?.expansionMap !== undefined) {
     throw new JsonLdError(
       '"expansionMap" not supported.',
       'jsonld.OptionsError');