1 files changed, 79 insertions, 0 deletions
diff --git a/node_modules/doiuse/utils/util.js b/node_modules/doiuse/utils/util.js
new file mode 100644
index 00000000..e9b323e9
--- /dev/null
+++ b/node_modules/doiuse/utils/util.js
@@ -0,0 +1,79 @@
+import { agents } from 'caniuse-lite';
+
+/** @typedef {RegExp|string|((value:string) => boolean)} FeatureCheck */
+
+/**
+ * @param {string} browserKey
+ * @param {string[]} [versions]
+ * @return {string}
+ */
+export function formatBrowserName(browserKey, versions) {
+  const entry = agents[browserKey];
+  const browserName = entry ? entry.browser : null;
+  if (!versions) {
+    return browserName || '';
+  }
+  return (`${browserName} (${versions.join(',')})`);
+}
+
+/**
+ *
+ * @param {FeatureCheck|FeatureCheck[]} check
+ * @param {?string|undefined} candidate
+ */
+export function performFeatureCheck(check, candidate) {
+  if (check == null || candidate == null) return false;
+  if (check instanceof RegExp) {
+    return check.test(candidate);
+  }
+  switch (typeof check) {
+    case 'string':
+      return candidate.includes(check);
+    case 'function':
+      return check(candidate);
+    case 'boolean':
+      return check;
+    case 'object':
+      if (Array.isArray(check)) {
+        return check.some((c) => performFeatureCheck(c, candidate));
+      }
+      // Fallthrough
+    default:
+      console.error(check);
+      throw new TypeError(`Unexpected feature check: ${check}`);
+  }
+}
+
+/**
+ * @param {FeatureCheck|FeatureCheck[]} selector
+ * @return {(rule:import('postcss').ChildNode) => boolean}
+ */
+export function checkSelector(selector) {
+  return (rule) => rule.type === 'rule'
+   && performFeatureCheck(selector, rule.selector);
+}
+
+/**
+ * @param {FeatureCheck|FeatureCheck[]} [name]
+ * @param {FeatureCheck|FeatureCheck[]} [parameters]
+ * @return {(rule:import('postcss').ChildNode) => boolean}
+ */
+export function checkAtRule(name, parameters) {
+  return (rule) => rule.type === 'atrule'
+    && performFeatureCheck(name, rule.name)
+    && (!parameters || performFeatureCheck(parameters, rule.params));
+}
+
+/**
+ * @see https://drafts.csswg.org/css-values/#lengths
+ * @see https://drafts.csswg.org/css-values/#number-value
+ * @param {string[]} units
+ * @return {(rule:import('postcss').ChildNode) => boolean}
+ */
+export function checkCSSLengthUnits(...units) {
+  const regexp = new RegExp(`(\\+-)?[\\d.]*\\.?\\d+(e(\\+-)?\\d+)?(${units.join('|')})`, 'i');
+  return (rule) => (
+    (rule.type === 'decl') ? performFeatureCheck(regexp, rule.value)
+      : ((rule.type === 'atrule') ? performFeatureCheck(regexp, rule.params)
+        : false));
+}