1 files changed, 54 insertions, 0 deletions
diff --git a/node_modules/csso/lib/compressor/clean/Atrule.js b/node_modules/csso/lib/compressor/clean/Atrule.js
new file mode 100644
index 00000000..d27db04b
--- /dev/null
+++ b/node_modules/csso/lib/compressor/clean/Atrule.js
@@ -0,0 +1,54 @@
+module.exports = function cleanAtrule(node, item, list) {
+    if (node.block) {
+        // otherwise removed at-rule don't prevent @import for removal
+        this.root.firstAtrulesAllowed = false;
+
+        if (node.block.type === 'Block' && node.block.declarations.isEmpty()) {
+            list.remove(item);
+            return;
+        }
+
+        if (node.block.type === 'StyleSheet' && node.block.rules.isEmpty()) {
+            list.remove(item);
+            return;
+        }
+    }
+
+    switch (node.name) {
+        case 'charset':
+            if (node.expression.sequence.isEmpty()) {
+                list.remove(item);
+                return;
+            }
+
+            // if there is any rule before @charset -> remove it
+            if (item.prev) {
+                list.remove(item);
+                return;
+            }
+
+            break;
+
+        case 'import':
+            if (!this.root.firstAtrulesAllowed) {
+                list.remove(item);
+                return;
+            }
+
+            // if there are some rules that not an @import or @charset before @import
+            // remove it
+            list.prevUntil(item.prev, function(rule) {
+                if (rule.type === 'Atrule') {
+                    if (rule.name === 'import' || rule.name === 'charset') {
+                        return;
+                    }
+                }
+
+                this.root.firstAtrulesAllowed = false;
+                list.remove(item);
+                return true;
+            }, this);
+
+            break;
+    }
+};