diff --git a/quickjs.c b/quickjs.c
index 6b097a302..b807c51e4 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -10254,6 +10254,13 @@ bool JS_IsMap(JSValueConst val)
     return JS_VALUE_GET_OBJ(val)->class_id == JS_CLASS_MAP;
 }
 
+bool JS_IsSet(JSValueConst val)
+{
+    if (JS_VALUE_GET_TAG(val) != JS_TAG_OBJECT)
+        return false;
+    return JS_VALUE_GET_OBJ(val)->class_id == JS_CLASS_SET;
+}
+
 bool JS_IsError(JSContext *ctx, JSValueConst val)
 {
     JSObject *p;
diff --git a/quickjs.h b/quickjs.h
index ba0718eb3..1f476a7fb 100644
--- a/quickjs.h
+++ b/quickjs.h
@@ -831,6 +831,7 @@ JS_EXTERN bool JS_SetConstructorBit(JSContext *ctx, JSValueConst func_obj, bool
 
 JS_EXTERN bool JS_IsRegExp(JSValueConst val);
 JS_EXTERN bool JS_IsMap(JSValueConst val);
+JS_EXTERN bool JS_IsSet(JSValueConst val);
 
 JS_EXTERN JSValue JS_NewArray(JSContext *ctx);
 // takes ownership of the values