diff --git a/background/storage.js b/background/storage.js
index b57cdf62..e373a8ed 100644
--- a/background/storage.js
+++ b/background/storage.js
@@ -1,9 +1,8 @@
-/* global getStyleWithNoCode styleSectionsEqual */
+/*
+  global getStyleWithNoCode styleSectionsEqual styleCodeEmpty RX_CSS_COMMENTS
+*/
 'use strict';
 
-const RX_NAMESPACE = /\s*(@namespace\s+(?:\S+\s+)?url\(http:\/\/.*?\);)\s*/g;
-const RX_CHARSET = /\s*@charset\s+(['"]).*?\1\s*;\s*/g;
-const RX_CSS_COMMENTS = /\/\*[\s\S]*?(?:\*\/|$)/g;
 // eslint-disable-next-line no-var
 var SLOPPY_REGEXP_PREFIX = '\0';
 
@@ -527,26 +526,6 @@ function getApplicableSections({
 }
 
 
-function styleCodeEmpty(code) {
-  // Collect the global section if it's not empty, not comment-only, not namespace-only.
-  const cmtOpen = code && code.indexOf('/*');
-  if (cmtOpen >= 0) {
-    const cmtCloseLast = code.lastIndexOf('*/');
-    if (cmtCloseLast < 0) {
-      code = code.substr(0, cmtOpen);
-    } else {
-      code = code.substr(0, cmtOpen) +
-        code.substring(cmtOpen, cmtCloseLast + 2).replace(RX_CSS_COMMENTS, '') +
-        code.substr(cmtCloseLast + 2);
-    }
-  }
-  if (!code || !code.trim()) return true;
-  if (code.includes('@namespace')) code = code.replace(RX_NAMESPACE, '').trim();
-  if (code.includes('@charset')) code = code.replace(RX_CHARSET, '').trim();
-  return !code;
-}
-
-
 function invalidateCache({added, updated, deletedId} = {}) {
   if (!cachedStyles.list) return;
   const id = added ? added.id : updated ? updated.id : deletedId;
diff --git a/background/util.js b/background/util.js
new file mode 100644
index 00000000..1bd2f0f5
--- /dev/null
+++ b/background/util.js
@@ -0,0 +1,24 @@
+'use strict';
+
+const RX_NAMESPACE = /\s*(@namespace\s+(?:\S+\s+)?url\(http:\/\/.*?\);)\s*/g;
+const RX_CHARSET = /\s*@charset\s+(['"]).*?\1\s*;\s*/g;
+const RX_CSS_COMMENTS = /\/\*[\s\S]*?(?:\*\/|$)/g;
+
+function styleCodeEmpty(code) {
+  // Collect the global section if it's not empty, not comment-only, not namespace-only.
+  const cmtOpen = code && code.indexOf('/*');
+  if (cmtOpen >= 0) {
+    const cmtCloseLast = code.lastIndexOf('*/');
+    if (cmtCloseLast < 0) {
+      code = code.substr(0, cmtOpen);
+    } else {
+      code = code.substr(0, cmtOpen) +
+        code.substring(cmtOpen, cmtCloseLast + 2).replace(RX_CSS_COMMENTS, '') +
+        code.substr(cmtCloseLast + 2);
+    }
+  }
+  if (!code || !code.trim()) return true;
+  if (code.includes('@namespace')) code = code.replace(RX_NAMESPACE, '').trim();
+  if (code.includes('@charset')) code = code.replace(RX_CHARSET, '').trim();
+  return !code;
+}