something is working

node_modules/mongoose/lib/schema/operators/exists.js

@@ -0,0 +1,12 @@
+'use strict';
+
+const castBoolean = require('../../cast/boolean');
+
+/*!
+ * ignore
+ */
+
+module.exports = function(val) {
+  const path = this != null ? this.path : null;
+  return castBoolean(val, path);
+};