Add Markdown getter API

src/lib/markdown.ts

@@ -0,0 +1,88 @@
+import { join } from 'node:path'
+import * as fs from 'node:fs/promises'
+import { remark } from 'remark'
+import remarkHeadingId from 'remark-heading-id'
+
+import html from 'remark-html'
+import matter from 'gray-matter'
+
+const { NEXT_PUBLIC_ADRESSE_URL, NODE_ENV } = process.env
+
+// fix unknown property on matter.GrayMatterFile
+// https://github.com/jonschlinkert/gray-matter/issues/160
+interface GreyMatter extends matter.GrayMatterFile<string> {
+  isEmpty?: boolean
+}
+
+export type DataType = {
+  aside?: Array<{ data: { contentHtml: string, data: { title: string } } }>
+}
+
+export type MarkdownType = {
+  fileName: string,
+  excerpt?: string,
+  contentHtml?: string,
+  data?: DataType,
+  isEmpty?: boolean,
+}
+
+const extractMarkdown = async (
+  fileContents: string,
+  callback: (filename: string, host?: string | undefined) => Promise<{}>,
+  filename: string,
+  host?: string
+): Promise<MarkdownType> => {
+  const { content, data = {}, excerpt, isEmpty }: GreyMatter = matter(fileContents)
+
+  const processedContent = await remark()
+    .use(remarkHeadingId, { defaults: true, uniqueDefaults: true })
+    .use(html)
+    .process(content)
+  const contentHtml = processedContent.toString()
+
+  let aside
+  if (!isEmpty && data?.aside) {
+    try {
+      const asideContent = data.aside.map(
+        (aside: { filename: string | undefined }) => aside?.filename && callback(aside.filename, host)
+      )
+      aside = (await Promise.all(asideContent)).map((content, i) => ({ ...data.aside[i], data: content }))
+    }
+    catch (error) {
+      if (NODE_ENV === 'development') console.error(error)
+    }
+  }
+
+  return {
+    fileName: filename,
+    excerpt,
+    contentHtml,
+    data: { ...data, ...(aside ? { aside } : {}) },
+    isEmpty,
+  }
+}
+
+export async function getMarkdown(filename: string = 'sample') {
+  'use server'
+
+  try {
+    const filePath = join(process.cwd(), 'public', 'markdown', `${filename}.md`);
+    const fileContents = await fs.readFile(filePath, 'utf8');
+    return extractMarkdown(fileContents, getMarkdown, filename)
+  }
+  catch (error) {
+    if (NODE_ENV === 'development') console.error(error)
+    return {}
+  }
+}
+
+export async function fetchMarkdown(filename: string = 'sample', host = NEXT_PUBLIC_ADRESSE_URL) {
+  try {
+    const fileContents = await fetch(`${host}/markdown/${filename}.md`).then(response => response.text())
+    return extractMarkdown(fileContents, fetchMarkdown, filename, host)
+  }
+  catch (error) {
+    if (NODE_ENV === 'development') console.error(error)
+    return {}
+  }
+}