feat(monorepo): use tailwindcss v4 in monorepo example (#6724)

* feat(monorepo): use tailwindcss v4 in monorepo example

* feat(shadcn): add monorepo tailwind detection

* feat: update default monorepo template

* fix: minor fixes

* chore(shadcn): changeset

* docs(www): update monorepo docs

* docs: updates

---------

Co-authored-by: shadcn <m@shadcn.com>

Author: Kaikaikaifang

.changeset/cold-impalas-call.md

@@ -0,0 +1,5 @@
+---
+"shadcn": patch
+---
+
+support for version detection in monorepo

apps/www/content/docs/components-json.mdx

@@ -51,7 +51,7 @@ See the <Link href="/docs/installation">installation section</Link> for how to s
 
 ### tailwind.config
 
-Path to where your `tailwind.config.js` file is located.
+Path to where your `tailwind.config.js` file is located. **For Tailwind CSS v4, leave this blank.**
 
 ```json title="components.json"
 {

apps/www/content/docs/monorepo.mdx

@@ -3,13 +3,6 @@ title: Monorepo
 description: Using shadcn/ui components and CLI in a monorepo.
 ---
 
-<Callout>
-  **Note:** We're releasing monorepo support in the CLI as __experimental__.
-  Help us improve it by testing it out and sending feedback. If you have any
-  questions, please [reach out to
-  us](https://github.com/shadcn-ui/ui/discussions).
-</Callout>
-
 Until now, using shadcn/ui in a monorepo was a bit of a pain. You could add
 components using the CLI, but you had to manage where the components
 were installed and manually fix import paths.
@@ -47,6 +40,8 @@ and [Turborepo](https://turbo.build/repo/docs) as the build system.
 
 Everything is set up for you, so you can start adding components to your project.
 
+Note: The monorepo uses React 19 and Tailwind CSS v4.
+
 ### Add components to your project
 
 To add components to your project, run the `add` command **in the path of your app**.
@@ -118,7 +113,66 @@ turbo.json
 
 2. The `components.json` file must properly define aliases for the workspace. This tells the CLI how to import components, hooks, utilities, etc.
 
-```json title="apps/web/components.json"
+<Tabs defaultValue="v4">
+
+<TabsList>
+  <TabsTrigger value="v4">Tailwind CSS v4</TabsTrigger>
+  <TabsTrigger value="v3">Tailwind CSS v3</TabsTrigger>
+</TabsList>
+
+<TabsContent value="v4">
+
+```json showLineNumbers title="apps/web/components.json"
+{
+  "$schema": "https://ui.shadcn.com/schema.json",
+  "style": "new-york",
+  "rsc": true,
+  "tsx": true,
+  "tailwind": {
+    "config": "",
+    "css": "../../packages/ui/src/styles/globals.css",
+    "baseColor": "zinc",
+    "cssVariables": true
+  },
+  "iconLibrary": "lucide",
+  "aliases": {
+    "components": "@/components",
+    "hooks": "@/hooks",
+    "lib": "@/lib",
+    "utils": "@workspace/ui/lib/utils",
+    "ui": "@workspace/ui/components"
+  }
+}
+```
+
+```json showLineNumbers title="packages/ui/components.json"
+{
+  "$schema": "https://ui.shadcn.com/schema.json",
+  "style": "new-york",
+  "rsc": true,
+  "tsx": true,
+  "tailwind": {
+    "config": "",
+    "css": "src/styles/globals.css",
+    "baseColor": "zinc",
+    "cssVariables": true
+  },
+  "iconLibrary": "lucide",
+  "aliases": {
+    "components": "@workspace/ui/components",
+    "utils": "@workspace/ui/lib/utils",
+    "hooks": "@workspace/ui/hooks",
+    "lib": "@workspace/ui/lib",
+    "ui": "@workspace/ui/components"
+  }
+}
+```
+
+</TabsContent>
+
+<TabsContent value="v3">
+
+```json showLineNumbers title="apps/web/components.json"
 {
   "$schema": "https://ui.shadcn.com/schema.json",
   "style": "new-york",
@@ -141,7 +195,7 @@ turbo.json
 }
 ```
 
-```json title="packages/ui/components.json"
+```json showLineNumbers title="packages/ui/components.json"
 {
   "$schema": "https://ui.shadcn.com/schema.json",
   "style": "new-york",
@@ -164,12 +218,12 @@ turbo.json
 }
 ```
 
-3. Ensure you have the same `style`, `iconLibrary` and `baseColor` in both `components.json` files.
+</TabsContent>
 
-By following these requirements, the CLI will be able to install ui components, blocks, libs and hooks to the correct paths and handle imports for you.
+</Tabs>
 
-## Help us improve monorepo support
+3. Ensure you have the same `style`, `iconLibrary` and `baseColor` in both `components.json` files.
 
-We're releasing monorepo support in the CLI as **experimental**. Help us improve it by testing it out and sending feedback.
+4. **For Tailwind CSS v4, leave the `tailwind` config empty in the `components.json` file.**
 
-If you have any questions, please reach out to us on [GitHub Discussions](https://github.com/shadcn-ui/ui/discussions).
+By following these requirements, the CLI will be able to install ui components, blocks, libs and hooks to the correct paths and handle imports for you.

packages/shadcn/src/utils/get-project-info.ts

@@ -153,7 +153,15 @@ export async function getProjectInfo(cwd: string): Promise<ProjectInfo | null> {
 export async function getTailwindVersion(
   cwd: string
 ): Promise<ProjectInfo["tailwindVersion"]> {
-  const packageInfo = getPackageInfo(cwd)
+  const [packageInfo, config] = await Promise.all([
+    getPackageInfo(cwd),
+    getConfig(cwd),
+  ])
+
+  // If the config file is empty, we can assume that it's a v4 project.
+  if (config?.tailwind?.config === "") {
+    return "v4"
+  }
 
   if (
     !packageInfo?.dependencies?.tailwindcss &&

packages/shadcn/src/utils/transformers/transform-import.ts

@@ -21,12 +21,14 @@ export const transformImport: Transformer = async ({
     importDeclaration.setModuleSpecifier(moduleSpecifier)
 
     // Replace `import { cn } from "@/lib/utils"`
-    if (utilsImport === moduleSpecifier) {
+    if (utilsImport === moduleSpecifier || moduleSpecifier === "@/lib/utils") {
       const namedImports = importDeclaration.getNamedImports()
       const cnImport = namedImports.find((i) => i.getName() === "cn")
       if (cnImport) {
         importDeclaration.setModuleSpecifier(
-          moduleSpecifier.replace(utilsImport, config.aliases.utils)
+          utilsImport === moduleSpecifier
+            ? moduleSpecifier.replace(utilsImport, config.aliases.utils)
+            : config.aliases.utils
         )
       }
     }

templates/monorepo-next/apps/web/components.json

@@ -4,9 +4,9 @@
   "rsc": true,
   "tsx": true,
   "tailwind": {
-    "config": "../../packages/ui/tailwind.config.ts",
+    "config": "",
     "css": "../../packages/ui/src/styles/globals.css",
-    "baseColor": "zinc",
+    "baseColor": "neutral",
     "cssVariables": true
   },
   "iconLibrary": "lucide",

templates/monorepo-next/apps/web/package.json

@@ -7,24 +7,24 @@
     "dev": "next dev --turbopack",
     "build": "next build",
     "start": "next start",
-    "lint": "next lint"
+    "lint": "next lint",
+    "lint:fix": "next lint --fix",
+    "typecheck": "tsc --noEmit"
   },
   "dependencies": {
     "@workspace/ui": "workspace:*",
-    "lucide-react": "0.456.0",
-    "next-themes": "^0.4.3",
-    "next": "^15.1.0",
+    "lucide-react": "^0.475.0",
+    "next": "^15.2.0",
+    "next-themes": "^0.4.4",
     "react": "^19.0.0",
     "react-dom": "^19.0.0"
   },
   "devDependencies": {
     "@types/node": "^20",
-    "@types/react": "18.3.0",
-    "@types/react-dom": "18.3.1",
+    "@types/react": "^19",
+    "@types/react-dom": "^19",
     "@workspace/eslint-config": "workspace:^",
     "@workspace/typescript-config": "workspace:*",
-    "postcss": "^8",
-    "tailwindcss": "^3.4.1",
-    "typescript": "^5"
+    "typescript": "^5.7.3"
   }
 }

templates/monorepo-next/apps/web/tailwind.config.ts

@@ -14,7 +14,7 @@
   },
   "include": [
     "next-env.d.ts",
-    "next.config.mjs",
+    "next.config.ts",
     "**/*.ts",
     "**/*.tsx",
     ".next/types/**/*.ts"

templates/monorepo-next/apps/web/tsconfig.json

@@ -11,11 +11,11 @@
   "devDependencies": {
     "@workspace/eslint-config": "workspace:*",
     "@workspace/typescript-config": "workspace:*",
-    "prettier": "^3.2.5",
-    "turbo": "^2.3.0",
-    "typescript": "5.5.4"
+    "prettier": "^3.5.1",
+    "turbo": "^2.4.2",
+    "typescript": "5.7.3"
   },
-  "packageManager": "pnpm@9.12.3",
+  "packageManager": "pnpm@10.4.1",
   "engines": {
     "node": ">=20"
   }

templates/monorepo-next/package.json

@@ -9,17 +9,17 @@
     "./react-internal": "./react-internal.js"
   },
   "devDependencies": {
-    "@next/eslint-plugin-next": "^15.1.0",
-    "@typescript-eslint/eslint-plugin": "^8.15.0",
-    "@typescript-eslint/parser": "^8.15.0",
-    "eslint": "^9.15.0",
+    "@next/eslint-plugin-next": "^15.1.7",
+    "@typescript-eslint/eslint-plugin": "^8.24.1",
+    "@typescript-eslint/parser": "^8.24.1",
+    "eslint": "^9.20.1",
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-only-warn": "^1.1.0",
-    "eslint-plugin-react": "^7.37.2",
-    "eslint-plugin-react-hooks": "^5.0.0",
-    "eslint-plugin-turbo": "^2.3.0",
-    "globals": "^15.12.0",
-    "typescript": "^5.3.3",
-    "typescript-eslint": "^8.15.0"
+    "eslint-plugin-react": "^7.37.4",
+    "eslint-plugin-react-hooks": "^5.1.0",
+    "eslint-plugin-turbo": "^2.4.2",
+    "globals": "^15.15.0",
+    "typescript": "^5.7.3",
+    "typescript-eslint": "^8.24.1"
   }
 }

templates/monorepo-next/packages/eslint-config/package.json

@@ -4,9 +4,9 @@
   "rsc": true,
   "tsx": true,
   "tailwind": {
-    "config": "tailwind.config.ts",
+    "config": "",
     "css": "src/styles/globals.css",
-    "baseColor": "zinc",
+    "baseColor": "neutral",
     "cssVariables": true
   },
   "iconLibrary": "lucide",

templates/monorepo-next/packages/ui/components.json

@@ -7,34 +7,31 @@
     "lint": "eslint . --max-warnings 0"
   },
   "dependencies": {
-    "@radix-ui/react-slot": "^1.1.1",
-    "class-variance-authority": "^0.7.0",
+    "@radix-ui/react-slot": "^1.1.2",
+    "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
-    "lucide-react": "0.456.0",
-    "next-themes": "^0.4.3",
+    "lucide-react": "^0.475.0",
+    "next-themes": "^0.4.4",
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
-    "tailwind-merge": "^2.5.4",
+    "tailwind-merge": "^3.0.1",
     "tailwindcss-animate": "^1.0.7",
-    "zod": "^3.23.8"
+    "zod": "^3.24.2"
   },
   "devDependencies": {
-    "@turbo/gen": "^2.2.3",
-    "@types/node": "^22.9.0",
-    "@types/react": "18.3.0",
-    "@types/react-dom": "18.3.1",
+    "@tailwindcss/postcss": "^4.0.8",
+    "@turbo/gen": "^2.4.2",
+    "@types/node": "^20",
+    "@types/react": "^19",
+    "@types/react-dom": "^19",
     "@workspace/eslint-config": "workspace:*",
     "@workspace/typescript-config": "workspace:*",
-    "autoprefixer": "^10.4.20",
-    "postcss": "^8.4.47",
-    "react": "^18.3.1",
-    "tailwindcss": "^3.4.14",
-    "typescript": "^5.6.3"
+    "tailwindcss": "^4.0.8",
+    "typescript": "^5.7.3"
   },
   "exports": {
     "./globals.css": "./src/styles/globals.css",
     "./postcss.config": "./postcss.config.mjs",
-    "./tailwind.config": "./tailwind.config.ts",
     "./lib/*": "./src/lib/*.ts",
     "./components/*": "./src/components/*.tsx",
     "./hooks/*": "./src/hooks/*.ts"

templates/monorepo-next/packages/ui/package.json

@@ -1,9 +1,6 @@
 /** @type {import('postcss-load-config').Config} */
 const config = {
-  plugins: {
-    tailwindcss: {},
-    autoprefixer: {},
-  },
+    plugins: { "@tailwindcss/postcss": {} },
 };
 
-export default config;
+export default config;