docs: support detecting broken link cross-projects (#10483)

* docs: support detecting broken link cross-projects

* remove double separators

www/apps/api-reference/markdown/admin.mdx

@@ -832,7 +832,7 @@ If you click on the workflow, you'll view a reference of that workflow, includin
 
 This is useful if you want to extend an API route and pass additional data or perform custom actions.
 
-Refer to [this guide](https://docs.medusajs.com/learn/customization/extend-features/extend-create-product) to find an example of extending an API route.
+Refer to [this guide](!docs!/learn/customization/extend-features/extend-create-product) to find an example of extending an API route.
 
 <Feedback
   event="survey_api-ref"

www/apps/api-reference/markdown/client-libraries.mdx

@@ -4,7 +4,7 @@ import DownloadFull from "@/components/DownloadFull"
 
 <H3 className="!mt-0">Just Getting Started?</H3>
 
-Check out the [Medusa v2 Documentation](https://docs.medusajs.com).
+Check out the [Medusa v2 Documentation](!docs!).
 
 <Space bottom={8} />
 
@@ -16,7 +16,7 @@ To use Medusa's JS SDK library, install the following packages in your project (
 npm install @medusajs/js-sdk@latest @medusajs/types@latest
 ```
 
-Learn more about the JS SDK in [this documentation](https://docs.medusajs.com/resources/js-sdk).
+Learn more about the JS SDK in [this documentation](!resources!/js-sdk).
 
 ### Download Full Reference
 

www/apps/api-reference/markdown/store.mdx

@@ -831,7 +831,7 @@ If you click on the workflow, you'll view a reference of that workflow, includin
 
 This is useful if you want to extend an API route and pass additional data or perform custom actions.
 
-Refer to [this guide](https://docs.medusajs.com/learn/customization/extend-features/extend-create-product) to find an example of extending an API route.
+Refer to [this guide](!docs!/learn/customization/extend-features/extend-create-product) to find an example of extending an API route.
 
 <Feedback
   event="survey_api-ref"

www/apps/api-reference/next.config.mjs

@@ -2,6 +2,11 @@ import createMDX from "@next/mdx"
 import bundleAnalyzer from "@next/bundle-analyzer"
 import rehypeMdxCodeProps from "rehype-mdx-code-props"
 import rehypeSlug from "rehype-slug"
+import {
+  brokenLinkCheckerPlugin,
+  crossProjectLinksPlugin,
+} from "remark-rehype-plugins"
+import path from "path"
 
 /** @type {import('next').NextConfig} */
 const nextConfig = {
@@ -28,6 +33,48 @@ const nextConfig = {
 const withMDX = createMDX({
   options: {
     rehypePlugins: [
+      [
+        brokenLinkCheckerPlugin,
+        {
+          crossProjects: {
+            docs: {
+              projectPath: path.resolve("..", "book"),
+            },
+            resources: {
+              projectPath: path.resolve("..", "resources"),
+              hasGeneratedSlugs: true,
+            },
+            ui: {
+              projectPath: path.resolve("..", "ui"),
+              contentPath: "src/content/docs",
+            },
+          },
+        },
+      ],
+      [
+        crossProjectLinksPlugin,
+        {
+          baseUrl: process.env.NEXT_PUBLIC_BASE_URL,
+          projectUrls: {
+            docs: {
+              url: process.env.NEXT_PUBLIC_DOCS_URL,
+              path: "",
+            },
+            resources: {
+              url: process.env.NEXT_PUBLIC_RESOURCES_URL,
+            },
+            "user-guide": {
+              url: process.env.NEXT_PUBLIC_USER_GUIDE_URL,
+            },
+            ui: {
+              url: process.env.NEXT_PUBLIC_UI_URL,
+            },
+          },
+          useBaseUrl:
+            process.env.NODE_ENV === "production" ||
+            process.env.VERCEL_ENV === "production",
+        },
+      ],
       [
         rehypeMdxCodeProps,
         {

www/apps/api-reference/package.json

@@ -41,6 +41,7 @@
     "react-transition-group": "^4.4.5",
     "rehype-mdx-code-props": "^3.0.1",
     "rehype-slug": "^6.0.0",
+    "remark-rehype-plugins": "*",
     "slugify": "^1.6.6",
     "swr": "^2.2.0",
     "tailwind": "*",