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node_modules/postcss-discard-overridden/src/index.js

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+'use strict';
+const OVERRIDABLE_RULES = new Set(['keyframes', 'counter-style']);
+const SCOPE_RULES = new Set(['media', 'supports']);
+
+/**
+ * @param {string} prop
+ * @return {string}
+ */
+function vendorUnprefixed(prop) {
+  return prop.replace(/^-\w+-/, '');
+}
+
+/**
+ * @param {string} name
+ * @return {boolean}
+ */
+function isOverridable(name) {
+  return OVERRIDABLE_RULES.has(vendorUnprefixed(name.toLowerCase()));
+}
+
+/**
+ * @param {string} name
+ * @return {boolean}
+ */
+function isScope(name) {
+  return SCOPE_RULES.has(vendorUnprefixed(name.toLowerCase()));
+}
+
+/**
+ * @param {import('postcss').AtRule} node
+ * @return {string}
+ */
+function getScope(node) {
+  /** @type {import('postcss').Container<import('postcss').ChildNode> | import('postcss').Document | undefined} */
+  let current = node.parent;
+
+  const chain = [node.name.toLowerCase(), node.params];
+
+  while (current) {
+    if (
+      current.type === 'atrule' &&
+      isScope(/** @type import('postcss').AtRule */ (current).name)
+    ) {
+      chain.unshift(
+        /** @type import('postcss').AtRule */ (current).name +
+          ' ' +
+          /** @type import('postcss').AtRule */ (current).params
+      );
+    }
+    current = current.parent;
+  }
+
+  return chain.join('|');
+}
+
+/**
+ * @type {import('postcss').PluginCreator<void>}
+ * @return {import('postcss').Plugin}
+ */
+function pluginCreator() {
+  return {
+    postcssPlugin: 'postcss-discard-overridden',
+    prepare() {
+      const cache = new Map();
+      /** @type {{node: import('postcss').AtRule, scope: string}[]} */
+      const rules = [];
+
+      return {
+        OnceExit(css) {
+          css.walkAtRules((node) => {
+            if (isOverridable(node.name)) {
+              const scope = getScope(node);
+
+              cache.set(scope, node);
+              rules.push({
+                node,
+                scope,
+              });
+            }
+          });
+
+          rules.forEach((rule) => {
+            if (cache.get(rule.scope) !== rule.node) {
+              rule.node.remove();
+            }
+          });
+        },
+      };
+    },
+  };
+}
+
+pluginCreator.postcss = true;
+module.exports = pluginCreator;