1 files changed, 2 insertions, 0 deletions
diff --git a/lib/compress.js b/lib/compress.js
index a48d0c9a..142728c2 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2224,6 +2224,8 @@ merge(Compressor.prototype, {
             "split",
             "substr",
             "substring",
+            "toLowerCase",
+            "toUpperCase",
             "trim",
         ].concat(object_fns),
     };