fix: normalize post metadata and tag helpers

lib/posts.ts

@@ -18,10 +18,65 @@ export interface PostMeta {
 
 export type Post = PostMeta
 
+export interface TagMeta {
+  slug: string
+  label: string
+  count: number
+}
+
+const normalizeString = (value: unknown, fallback: string): string => {
+  if (typeof value === 'string') return value
+  if (value instanceof Date && !Number.isNaN(value.getTime())) return value.toISOString()
+  if (typeof value === 'number' || typeof value === 'boolean') return String(value)
+  return fallback
+}
+
+const normalizeOptionalString = (value: unknown): string | null => {
+  if (typeof value !== 'string') return null
+
+  const normalized = value.trim()
+  return normalized.length > 0 ? normalized : null
+}
+
+const normalizeTags = (value: unknown): string[] => {
+  const values = Array.isArray(value) ? value : typeof value === 'string' ? [value] : []
+
+  return values
+    .map((tag) => normalizeString(tag, '').trim())
+    .filter((tag) => tag.length > 0)
+}
+
+export const normalizePostData = (
+  slug: string,
+  data: Record<string, unknown>,
+  readingTime: number
+): PostMeta => ({
+  slug,
+  title: normalizeString(data.title, slug),
+  date: normalizeString(data.date, 'Unknown'),
+  excerpt: normalizeString(data.excerpt, ''),
+  tags: normalizeTags(data.tags),
+  author: normalizeOptionalString(data.author),
+  coverImage: normalizeOptionalString(data.coverImage),
+  readingTime,
+})
+
+export const tagToSlug = (tag: string): string =>
+  tag
+    .normalize('NFKD')
+    .toLowerCase()
+    .replace(/[\u0300-\u036f]/g, '')
+    .replace(/\+/g, ' plus ')
+    .replace(/#/g, ' sharp ')
+    .replace(/[\\/]+/g, ' ')
+    .replace(/[^\p{L}\p{N}]+/gu, '-')
+    .replace(/-{2,}/g, '-')
+    .replace(/^-|-$/g, '')
+
 const getMdxFiles = cache(async () => {
   try {
     const files = await fs.promises.readdir(postsDirectory)
-    return files.filter((f) => f.endsWith('.mdx') || f.endsWith('.md'))
+    return files.filter((file) => file.endsWith('.mdx')).sort((a, b) => a.localeCompare(b))
   } catch {
     return []
   }
@@ -33,22 +88,11 @@ export const getPosts = cache(async (): Promise<PostMeta[]> => {
     files.map(async (file) => {
       const filePath = path.join(postsDirectory, file)
       const raw = await fs.promises.readFile(filePath, 'utf-8')
-      const { data } = matter(raw)
+      const { data, content } = matter(raw)
-      const slug = file.replace(/\.(mdx|md)$/, '')
+      const slug = file.replace(/\.mdx$/, '')
-      // Compute reading time from content (everything after frontmatter)
+      const readingTime = getReadingTime(content)
-      const content = raw.split(/---\n*\n*/).slice(2).join('\n')
-      const readingTime = Math.max(1, Math.ceil(content.split(/\s+/).length / 200))
 
-      return {
+      return normalizePostData(slug, data, readingTime)
-        slug,
-        title: data.title ?? slug,
-        date: data.date ?? 'Unknown',
-        excerpt: data.excerpt ?? '',
-        tags: data.tags ?? [],
-        author: data.author ?? null,
-        coverImage: data.coverImage ?? null,
-        readingTime,
-      }
     })
   ).then((posts) =>
     posts.sort((a, b) => new Date(b.date).getTime() - new Date(a.date).getTime())
@@ -57,29 +101,53 @@ export const getPosts = cache(async (): Promise<PostMeta[]> => {
 
 export const getPost = async (slug: string): Promise<Post | null> => {
   const files = await getMdxFiles()
-  const file = files.find((f) => f.replace(/\.(mdx|md)$/, '') === slug)
+  const file = files.find((f) => f.replace(/\.mdx$/, '') === slug)
   if (!file) return null
 
   const filePath = path.join(postsDirectory, file)
   const raw = await fs.promises.readFile(filePath, 'utf8')
-  const { data } = matter(raw)
+  const { data, content } = matter(raw)
 
-  const contentForReadingTime = raw.replace(/^---[\s\S]*?---\s*?/, '')
+  return normalizePostData(slug, data, getReadingTime(content)) satisfies Post
-  const readingTime = Math.max(1, Math.ceil(contentForReadingTime.split(/\s+/).filter(Boolean).length / 200))
-
-  return {
-    slug,
-    title: data.title ?? slug,
-    date: data.date ?? 'Unknown',
-    excerpt: data.excerpt ?? '',
-    tags: data.tags ?? [],
-    author: data.author ?? null,
-    coverImage: data.coverImage ?? null,
-    readingTime,
-  } satisfies Post
 }
 
 export const getReadingTime = (content: string): number => {
   const words = content.replace(/<[^>]*>/g, '').trim().split(/\s+/).filter(Boolean).length
   return Math.max(1, Math.ceil(words / 200))
 }
+
+export const getAllTags = cache(async (): Promise<TagMeta[]> => {
+  const posts = await getPosts()
+  const tags = new Map<string, TagMeta>()
+
+  posts.forEach((post) => {
+    const postTagSlugs = new Set<string>()
+
+    post.tags.forEach((tag) => {
+      const slug = tagToSlug(tag)
+      if (!slug || postTagSlugs.has(slug)) return
+
+      postTagSlugs.add(slug)
+      const existing = tags.get(slug)
+
+      if (existing) {
+        existing.count += 1
+        if (tag.localeCompare(existing.label) < 0) existing.label = tag
+        return
+      }
+
+      tags.set(slug, { slug, label: tag, count: 1 })
+    })
+  })
+
+  return Array.from(tags.values()).sort(
+    (a, b) => a.label.localeCompare(b.label) || a.slug.localeCompare(b.slug)
+  )
+})
+
+export const getPostsByTag = cache(async (tagSlug: string): Promise<PostMeta[]> => {
+  const posts = await getPosts()
+  const normalizedTagSlug = tagToSlug(tagSlug)
+
+  return posts.filter((post) => post.tags.some((tag) => tagToSlug(tag) === normalizedTagSlug))
+})