🤖 Claude Code: Add extract section to md-utils

packages/util-md/package.json

@@ -20,7 +20,8 @@
     "./find-footnotes": "./src/find-footnotes.js",
     "./find-date": "./src/find-date.js",
     "./find-html-tags": "./src/find-html-tags.js",
-    "./string-utils": "./src/string-utils.js"
+    "./string-utils": "./src/string-utils.js",
+    "./extract-section": "./src/extract-section.js"
   },
   "scripts": {
     "test": "uvu src '.test.([mc]js|[jt]sx?)$'",

packages/util-md/src/extract-section.js

@@ -0,0 +1,80 @@
+const { findCodeBlocks } = require('./find-code-blocks')
+const SPECIAL_REPLACE_CHAR = '▣'
+const SPECIAL_REPLACE_REGEX = new RegExp(SPECIAL_REPLACE_CHAR, 'g')
+
+/**
+ * Extract a section from markdown content based on a header title
+ * @param {string} content - The markdown content to extract from
+ * @param {string} sectionTitle - The title of the section to extract (without ## prefix)
+ * @param {Object} [options] - Options for extraction
+ * @param {number} [options.level=2] - The heading level to match (default: 2)
+ * @param {boolean} [options.includeHeader=false] - Whether to include the header in the result (default: false)
+ * @param {boolean} [options.caseSensitive=false] - Whether to match case-sensitively (default: false)
+ * @returns {string|undefined} The extracted section content, or undefined if not found
+ */
+function extractSection(content, sectionTitle, options = {}) {
+  if (!content || typeof content !== 'string') {
+    return undefined
+  }
+
+  if (!sectionTitle || typeof sectionTitle !== 'string') {
+    return undefined
+  }
+
+  const {
+    level = 2,
+    includeHeader = false,
+    caseSensitive = false
+  } = options
+
+  // Fix conflicting # in code blocks
+  const codeBlocks = findCodeBlocks(content)
+  if (codeBlocks && codeBlocks.blocks && codeBlocks.blocks.length) {
+    for (let i = 0; i < codeBlocks.blocks.length; i++) {
+      const block = codeBlocks.blocks[i]
+      const cleanBlock = block.block.replace(/#/g, SPECIAL_REPLACE_CHAR)
+      content = content.replace(block.block, cleanBlock)
+    }
+  }
+
+  // Create the header pattern based on level
+  const headerPrefix = '#'.repeat(level)
+  const flags = caseSensitive ? 'g' : 'gi'
+
+  // Escape special regex characters in the section title
+  const escapedTitle = sectionTitle.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
+
+  // Create regex pattern to match the section
+  // Match the header and capture content until next header of same or higher level
+  const higherLevelPattern = level === 1 ? '#' : `#{1,${level}}`
+
+  // Try to match with a simpler approach first
+  const regex = new RegExp(
+    `${headerPrefix}\\s+${escapedTitle}[ \\t]*\\n([\\s\\S]*?)(?=\\n${higherLevelPattern}\\s|$)`,
+    flags.includes('i') ? 'i' : ''
+  )
+
+  const match = content.match(regex)
+
+  if (!match) {
+    return undefined
+  }
+
+  let result = match[1]?.trim()
+
+  // Include the header if requested
+  if (includeHeader) {
+    const headerMatch = match[0].split('\n')[0]
+    result = headerMatch + '\n\n' + result
+  }
+
+  if (result.indexOf(SPECIAL_REPLACE_CHAR) !== -1) {
+    result = result.replace(SPECIAL_REPLACE_REGEX, '#')
+  }
+
+  return result
+}
+
+module.exports = {
+  extractSection
+}