1 files changed, 109 insertions, 0 deletions
diff --git a/node_modules/csso/cjs/restructure/1-mergeAtrule.cjs b/node_modules/csso/cjs/restructure/1-mergeAtrule.cjs
new file mode 100644
index 00000000..308587a0
--- /dev/null
+++ b/node_modules/csso/cjs/restructure/1-mergeAtrule.cjs
@@ -0,0 +1,109 @@
+'use strict';
+
+const cssTree = require('css-tree');
+
+const { hasOwnProperty } = Object.prototype;
+
+function addRuleToMap(map, item, list, single) {
+    const node = item.data;
+    const name = cssTree.keyword(node.name).basename;
+    const id = node.name.toLowerCase() + '/' + (node.prelude ? node.prelude.id : null);
+
+    if (!hasOwnProperty.call(map, name)) {
+        map[name] = Object.create(null);
+    }
+
+    if (single) {
+        delete map[name][id];
+    }
+
+    if (!hasOwnProperty.call(map[name], id)) {
+        map[name][id] = new cssTree.List();
+    }
+
+    map[name][id].append(list.remove(item));
+}
+
+function relocateAtrules(ast, options) {
+    const collected = Object.create(null);
+    let topInjectPoint = null;
+
+    ast.children.forEach(function(node, item, list) {
+        if (node.type === 'Atrule') {
+            const name = cssTree.keyword(node.name).basename;
+
+            switch (name) {
+                case 'keyframes':
+                    addRuleToMap(collected, item, list, true);
+                    return;
+
+                case 'media':
+                    if (options.forceMediaMerge) {
+                        addRuleToMap(collected, item, list, false);
+                        return;
+                    }
+                    break;
+            }
+
+            if (topInjectPoint === null &&
+                name !== 'charset' &&
+                name !== 'import') {
+                topInjectPoint = item;
+            }
+        } else {
+            if (topInjectPoint === null) {
+                topInjectPoint = item;
+            }
+        }
+    });
+
+    for (const atrule in collected) {
+        for (const id in collected[atrule]) {
+            ast.children.insertList(
+                collected[atrule][id],
+                atrule === 'media' ? null : topInjectPoint
+            );
+        }
+    }
+}
+function isMediaRule(node) {
+    return node.type === 'Atrule' && node.name === 'media';
+}
+
+function processAtrule(node, item, list) {
+    if (!isMediaRule(node)) {
+        return;
+    }
+
+    const prev = item.prev && item.prev.data;
+
+    if (!prev || !isMediaRule(prev)) {
+        return;
+    }
+
+    // merge @media with same query
+    if (node.prelude &&
+        prev.prelude &&
+        node.prelude.id === prev.prelude.id) {
+        prev.block.children.appendList(node.block.children);
+        list.remove(item);
+
+        // TODO: use it when we can refer to several points in source
+        // prev.loc = {
+        //     primary: prev.loc,
+        //     merged: node.loc
+        // };
+    }
+}
+
+function rejoinAtrule(ast, options) {
+    relocateAtrules(ast, options);
+
+    cssTree.walk(ast, {
+        visit: 'Atrule',
+        reverse: true,
+        enter: processAtrule
+    });
+}
+
+module.exports = rejoinAtrule;