feat: add 'reading-time' and word count

packages/next-mdx/package.json

@@ -45,7 +45,8 @@
     "gray-matter": "^4.0.2",
     "hasha": "^5.2.2",
     "next-mdx-remote": "^2.1.3",
-    "node-cache": "^5.1.2"
+    "node-cache": "^5.1.2",
+    "reading-time": "^1.3.0"
   },
   "peerDependencies": {
     "next": ">= 10.0.0",

packages/next-mdx/src/get-nodes.ts

@@ -1,6 +1,7 @@
 import { promises as fs } from "fs"
 import matter from "gray-matter"
 import hasha from "hasha"
+import readingTime from "reading-time"
 import { GetStaticPropsContext } from "next"
 import { Pluggable, Compiler } from "unified"
 import renderToString from "next-mdx-remote/render-to-string"
@@ -181,6 +182,11 @@ export async function getFileData(file: MdxFile): Promise<MdxFileData> {
 
   const { content, data: frontMatter } = matter(raw)
 
+  const word_count = content.split(/\s+/gu).length
+  const reading_time = readingTime(content)
+  frontMatter.reading_time = reading_time
+  frontMatter.word_count = word_count
+
   const fileData: MdxFileData = {
     hash,
     content,

packages/next-mdx/test/index.test.js

@@ -44,6 +44,8 @@ test("gets a node using slug", async () => {
   const post = await getNode("post", "post-one")
   expect(post.frontMatter.title).toBe("Post One")
   expect(post.url).toBe("/blog/post-one")
+  expect(post.frontMatter.word_count).toBe(71)
+  expect(post.frontMatter.reading_time.text).toBe("1 min read")
 
   const author = await getNode("author", "john-doe")
   expect(author.frontMatter.name).toBe("John Doe")

yarn.lock

@@ -10487,6 +10487,11 @@ readdirp@~3.5.0:
   dependencies:
     picomatch "^2.2.1"
 
+reading-time@^1.3.0:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/reading-time/-/reading-time-1.3.0.tgz#d13e74431589a4a9038669f24d5acbc08bbb015d"
+  integrity sha512-RJ8J5O6UvrclfZpcPSPuKusrdRfoY7uXXoYOOdeswZNtSkQaewT3919yz6RyloDBR+iwcUyz5zGOUjhgvfuv3g==
+
 rebass@^4.0.7:
   version "4.0.7"
   resolved "https://registry.yarnpkg.com/rebass/-/rebass-4.0.7.tgz#0a84e5558750c1f416c3baf41ec4c7fc8d64a98a"