docs: add prepare script to generate sidebar (#11894)

www/packages/docs-utils/src/find-title.ts

@@ -8,14 +8,27 @@ export function findMetadataTitle(content: string): string | undefined {
   return headingMatch?.groups?.title
 }
 
-const HEADING_REGEX = /# (?<title>.*)/
-
 export function findPageHeading(content: string): string | undefined {
-  const headingMatch = HEADING_REGEX.exec(content)
+  const headingMatch = /# (?<title>.*)/.exec(content)
 
   return headingMatch?.groups?.title
 }
 
+export function findAllPageHeadings({
+  content,
+  level = 1,
+}: {
+  content: string
+  level?: number
+}): string[] {
+  const regex = new RegExp(
+    `^${"#".repeat(level)}(?!#) (?<title>.*?)(?:\n|$)`,
+    "gm"
+  )
+  const matches = [...content.matchAll(regex)]
+  return matches.map((match) => match.groups?.title).filter(Boolean) as string[]
+}
+
 export function findPageTitle(filePath: string): string | undefined {
   const content = readFileSync(filePath, "utf-8")