diff --git a/lib/filters.ts b/lib/filters.ts
index b3d64f7..789b5ee 100644
--- a/lib/filters.ts
+++ b/lib/filters.ts
@@ -94,7 +94,7 @@ function *parseIntoRegexpInternal(str: string): Iterable<RegExp> {
 
   // multi-expression
   if (str.includes(",")) {
-    for (const part in str.split(",")) {
+    for (const part of str.split(",")) {
       yield *parseIntoRegexpInternal(part);
     }
     return;