refactor "notes" into "posts" (only on the backend)

lib/helpers/posts.ts

@@ -0,0 +1,135 @@
+import path from "path";
+import fs from "fs/promises";
+import { serialize } from "next-mdx-remote/serialize";
+import glob from "fast-glob";
+import pMap from "p-map";
+import pMemoize from "p-memoize";
+import matter from "gray-matter";
+import { formatDate } from "./format-date";
+import type { PostFrontMatter, PostWithSource } from "../../types";
+
+// path to directory with .mdx files, relative to project root
+export const POSTS_DIR = "./notes";
+
+// returns front matter and the **raw & uncompiled** markdown of a given slug
+export const getPostData = async (
+  slug: string
+): Promise<{
+  frontMatter: PostFrontMatter;
+  markdown: string;
+}> => {
+  const fullPath = path.join(process.cwd(), POSTS_DIR, `${slug}.mdx`);
+  const rawContent = await fs.readFile(fullPath, "utf8");
+  const { data, content } = matter(rawContent);
+
+  const { unified } = await import("unified");
+  const { remarkParse, remarkSmartypants, remarkRehype, rehypeSanitize, rehypeStringify } = await import(
+    "./remark-rehype-plugins"
+  );
+
+  // allow *very* limited markdown to be used in post titles
+  const parseTitle = async (title: string, allowedTags: string[] = []): Promise<string> => {
+    return String(
+      await unified()
+        .use(remarkParse)
+        .use(remarkSmartypants, {
+          quotes: true,
+          dashes: "oldschool",
+          backticks: false,
+          ellipses: false,
+        })
+        .use(remarkRehype)
+        .use(rehypeSanitize, { tagNames: allowedTags })
+        .use(rehypeStringify)
+        .process(title)
+    );
+  };
+
+  // process title as both plain and stylized
+  const [title, htmlTitle] = await Promise.all([
+    parseTitle(data.title),
+    parseTitle(data.title, ["code", "em", "strong"]),
+  ]);
+
+  // return both the parsed YAML front matter (with a few amendments) and the raw, unparsed markdown content
+  return {
+    frontMatter: {
+      ...(data as Partial<PostFrontMatter>),
+      // zero markdown title:
+      title,
+      htmlTitle,
+      slug,
+      permalink: `${process.env.NEXT_PUBLIC_BASE_URL || ""}/${POSTS_DIR}/${slug}/`,
+      date: formatDate(data.date), // validate/normalize the date string provided from front matter
+    },
+    markdown: content,
+  };
+};
+
+// fully parses MDX into JS and returns *everything* about a post
+export const compilePost = async (slug: string): Promise<PostWithSource> => {
+  const { frontMatter, markdown } = await getPostData(slug);
+
+  const { remarkGfm, remarkSmartypants, remarkUnwrapImages, rehypeSlug, rehypePrism } = await import(
+    "./remark-rehype-plugins"
+  );
+
+  const { compiledSource } = await serialize(markdown, {
+    parseFrontmatter: false,
+    mdxOptions: {
+      remarkPlugins: [
+        // @ts-ignore
+        [remarkGfm, { singleTilde: false }],
+        [
+          // @ts-ignore
+          remarkSmartypants,
+          {
+            quotes: true,
+            dashes: "oldschool",
+            backticks: false,
+            ellipses: false,
+          },
+        ],
+        // @ts-ignore
+        [remarkUnwrapImages],
+      ],
+      rehypePlugins: [
+        // @ts-ignore
+        [rehypeSlug],
+        // @ts-ignore
+        [rehypePrism, { ignoreMissing: true }],
+      ],
+    },
+  });
+
+  return {
+    frontMatter,
+    source: {
+      compiledSource,
+    },
+  };
+};
+
+export const getPostSlugs = pMemoize(async (): Promise<string[]> => {
+  // list all .mdx files in POSTS_DIR
+  const mdxFiles = await glob("*.mdx", {
+    cwd: path.join(process.cwd(), POSTS_DIR),
+    dot: false,
+  });
+
+  // strip the .mdx extensions from filenames
+  const slugs = mdxFiles.map((fileName) => fileName.replace(/\.mdx$/, ""));
+
+  return slugs;
+});
+
+// returns the parsed front matter of ALL posts, sorted reverse chronologically
+export const getAllPosts = pMemoize(async (): Promise<PostFrontMatter[]> => {
+  // for each post, query its front matter
+  const data = await pMap(await getPostSlugs(), async (slug) => (await getPostData(slug)).frontMatter);
+
+  // sort the results by date
+  data.sort((post1, post2) => (post1.date > post2.date ? -1 : 1));
+
+  return data;
+});