1 files changed, 58 insertions, 0 deletions
diff --git a/node_modules/csso/lib/compressor/usage.js b/node_modules/csso/lib/compressor/usage.js
new file mode 100644
index 00000000..72d8b15b
--- /dev/null
+++ b/node_modules/csso/lib/compressor/usage.js
@@ -0,0 +1,58 @@
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+
+function buildMap(list, caseInsensitive) {
+    var map = Object.create(null);
+
+    if (!Array.isArray(list)) {
+        return false;
+    }
+
+    for (var i = 0; i < list.length; i++) {
+        var name = list[i];
+
+        if (caseInsensitive) {
+            name = name.toLowerCase();
+        }
+
+        map[name] = true;
+    }
+
+    return map;
+}
+
+function buildIndex(data) {
+    var scopes = false;
+
+    if (data.scopes && Array.isArray(data.scopes)) {
+        scopes = Object.create(null);
+
+        for (var i = 0; i < data.scopes.length; i++) {
+            var list = data.scopes[i];
+
+            if (!list || !Array.isArray(list)) {
+                throw new Error('Wrong usage format');
+            }
+
+            for (var j = 0; j < list.length; j++) {
+                var name = list[j];
+
+                if (hasOwnProperty.call(scopes, name)) {
+                    throw new Error('Class can\'t be used for several scopes: ' + name);
+                }
+
+                scopes[name] = i + 1;
+            }
+        }
+    }
+
+    return {
+        tags: buildMap(data.tags, true),
+        ids: buildMap(data.ids),
+        classes: buildMap(data.classes),
+        scopes: scopes
+    };
+}
+
+module.exports = {
+    buildIndex: buildIndex
+};