add: add support for old ios regex

Author: hiepxanh

lib/index.js

@@ -126,8 +126,24 @@ function exitLiteralAutolink(token) {
   this.exit(token)
 }
 
-/** @type {FromMarkdownTransform} */
-function transformGfmAutolinkLiterals(tree) {
+// Regex support detector
+const regexSupport = {
+  lookbehind: (() => {
+    try {
+      // Using regex literal instead of RegExp constructor
+      ;/(?<=x)/.test('x')
+      return true
+    } catch {
+      return false
+    }
+  })()
+}
+
+/**
+ * Modern version of autolink transform using lookbehind
+ * @type {FromMarkdownTransform}
+ */
+function modernAutolinkTransform(tree) {
   findAndReplace(
     tree,
     [
@@ -138,6 +154,45 @@ function transformGfmAutolinkLiterals(tree) {
   )
 }
 
+/**
+ * Legacy version of autolink transform for older Node.js versions
+ * @type {FromMarkdownTransform}
+ */
+function legacyAutolinkTransform(tree) {
+  findAndReplace(
+    tree,
+    [
+      [/(https?:\/\/|www(?=\.))([-.\w]+)([^ \t\r\n]*)/gi, findUrl],
+      [/(^|\s|\p{P}|\p{S})([-.\w+]+)@([-\w]+(?:\.[-\w]+)+)/gu, findEmailLegacy]
+    ],
+    {ignore: ['link', 'linkReference']}
+  )
+}
+
+/**
+ * Helper function for legacy email matching
+ * @param {string} _ - Unused parameter
+ * @param {string} prefix - Email prefix
+ * @param {string} name - Email name
+ * @param {string} domain - Email domain
+ * @returns {*} The processed email
+ */
+function findEmailLegacy(_, prefix, name, domain) {
+  return findEmail(name + '@' + domain)
+}
+
+/**
+ * Main transform function that uses the appropriate version based on regex support
+ * @type {FromMarkdownTransform}
+ */
+function transformGfmAutolinkLiterals(tree) {
+  if (regexSupport.lookbehind) {
+    modernAutolinkTransform(tree)
+  } else {
+    legacyAutolinkTransform(tree)
+  }
+}
+
 /**
  * @type {ReplaceFunction}
  * @param {string} _

test/index.js

@@ -452,6 +452,15 @@ test('gfmAutolinkLiteralToMarkdown()', async function (t) {
   )
 })
 
+/**
+ * Normalizes line endings to Unix style (\n)
+ * @param {string} text - The text to normalize
+ * @returns {string} The normalized text
+ */
+function normalizeLineEndings(text) {
+  return text.replaceAll('\r\n', '\n')
+}
+
 test('fixtures', async function (t) {
   const root = new URL('fixture/', import.meta.url)
 
@@ -469,8 +478,10 @@ test('fixtures', async function (t) {
       const inputUrl = new URL(file, root)
       const expectedUrl = new URL(stem + '.html', root)
 
-      const input = await fs.readFile(inputUrl)
-      const expected = String(await fs.readFile(expectedUrl))
+      const input = normalizeLineEndings(String(await fs.readFile(inputUrl)))
+      const expected = normalizeLineEndings(
+        String(await fs.readFile(expectedUrl))
+      )
 
       const mdast = fromMarkdown(input, {
         extensions: [gfmAutolinkLiteral()],