1 files changed, 39 insertions, 0 deletions
diff --git a/node_modules/csso/lib/compressor/clean/Ruleset.js b/node_modules/csso/lib/compressor/clean/Ruleset.js
new file mode 100644
index 00000000..4622b215
--- /dev/null
+++ b/node_modules/csso/lib/compressor/clean/Ruleset.js
@@ -0,0 +1,39 @@
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+
+function cleanUnused(node, usageData) {
+    return node.selector.selectors.each(function(selector, item, list) {
+        var hasUnused = selector.sequence.some(function(node) {
+            switch (node.type) {
+                case 'Class':
+                    return usageData.classes && !hasOwnProperty.call(usageData.classes, node.name);
+
+                case 'Id':
+                    return usageData.ids && !hasOwnProperty.call(usageData.ids, node.name);
+
+                case 'Identifier':
+                    // ignore universal selector
+                    if (node.name !== '*') {
+                        // TODO: remove toLowerCase when type selectors will be normalized
+                        return usageData.tags && !hasOwnProperty.call(usageData.tags, node.name.toLowerCase());
+                    }
+
+                    break;
+            }
+        });
+
+        if (hasUnused) {
+            list.remove(item);
+        }
+    });
+}
+
+module.exports = function cleanRuleset(node, item, list, usageData) {
+    if (usageData) {
+        cleanUnused(node, usageData);
+    }
+
+    if (node.selector.selectors.isEmpty() ||
+        node.block.declarations.isEmpty()) {
+        list.remove(item);
+    }
+};