something is working

node_modules/mongoose/lib/helpers/schema/cleanPositionalOperators.js

@@ -0,0 +1,12 @@
+'use strict';
+
+/**
+ * For consistency's sake, we replace positional operator `$` and array filters
+ * `$[]` and `$[foo]` with `0` when looking up schema paths.
+ */
+
+module.exports = function cleanPositionalOperators(path) {
+  return path.
+    replace(/\.\$(\[[^\]]*\])?(?=\.)/g, '.0').
+    replace(/\.\$(\[[^\]]*\])?$/g, '.0');
+};