1 files changed, 71 insertions, 0 deletions
diff --git a/node_modules/csso/lib/usage.js b/node_modules/csso/lib/usage.js
new file mode 100644
index 00000000..1618e931
--- /dev/null
+++ b/node_modules/csso/lib/usage.js
@@ -0,0 +1,71 @@
+const { hasOwnProperty } = Object.prototype;
+
+function buildMap(list, caseInsensitive) {
+    const map = Object.create(null);
+
+    if (!Array.isArray(list)) {
+        return null;
+    }
+
+    for (let name of list) {
+        if (caseInsensitive) {
+            name = name.toLowerCase();
+        }
+
+        map[name] = true;
+    }
+
+    return map;
+}
+
+function buildList(data) {
+    if (!data) {
+        return null;
+    }
+
+    const tags = buildMap(data.tags, true);
+    const ids = buildMap(data.ids);
+    const classes = buildMap(data.classes);
+
+    if (tags === null &&
+        ids === null &&
+        classes === null) {
+        return null;
+    }
+
+    return {
+        tags,
+        ids,
+        classes
+    };
+}
+
+export function buildIndex(data) {
+    let scopes = false;
+
+    if (data.scopes && Array.isArray(data.scopes)) {
+        scopes = Object.create(null);
+
+        for (let i = 0; i < data.scopes.length; i++) {
+            const list = data.scopes[i];
+
+            if (!list || !Array.isArray(list)) {
+                throw new Error('Wrong usage format');
+            }
+
+            for (const name of list) {
+                if (hasOwnProperty.call(scopes, name)) {
+                    throw new Error(`Class can't be used for several scopes: ${name}`);
+                }
+
+                scopes[name] = i + 1;
+            }
+        }
+    }
+
+    return {
+        whitelist: buildList(data),
+        blacklist: buildList(data.blacklist),
+        scopes
+    };
+}