feat(cna): add template (#41660)

Adds a new template for `app/` via `--experimental-app` flag.

## Bug

- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have a helpful link attached, see `contributing.md`

## Feature

- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see `contributing.md`

## Documentation / Examples

- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)

Co-authored-by: JJ Kasper <jj@jjsweb.site>

packages/create-next-app/create-app.ts

@@ -29,15 +29,21 @@ export async function createApp({
   example,
   examplePath,
   typescript,
+  experimentalApp,
 }: {
   appPath: string
   packageManager: PackageManager
   example?: string
   examplePath?: string
-  typescript?: boolean
+  typescript: boolean
+  experimentalApp: boolean
 }): Promise<void> {
   let repoInfo: RepoInfo | undefined
-  const template = typescript ? 'typescript' : 'default'
+  const template = experimentalApp
+    ? 'experimental-app'
+    : typescript
+    ? 'typescript'
+    : 'default'
 
   if (example) {
     let repoUrl: URL | undefined
@@ -238,7 +244,7 @@ export async function createApp({
     /**
      * TypeScript projects will have type definitions and other devDependencies.
      */
-    if (typescript) {
+    if (template !== 'default') {
       devDependencies.push(
         'typescript',
         '@types/react',
@@ -273,7 +279,7 @@ export async function createApp({
       const devInstallFlags = { devDependencies: true, ...installFlags }
       await install(root, devDependencies, devInstallFlags)
     }
-    console.log()
+    console.log('\nInitializing project with template: ', template, '\n')
     /**
      * Copy the template files to the target directory.
      */

packages/create-next-app/index.ts

@@ -24,6 +24,13 @@ const program = new Commander.Command(packageJson.name)
     `
 
   Initialize as a TypeScript project.
+`
+  )
+  .option(
+    '--experimental-app',
+    `
+
+  Initialize as a \`app/\` directory project.
 `
   )
   .option(
@@ -136,6 +143,7 @@ async function run(): Promise<void> {
       example: example && example !== 'default' ? example : undefined,
       examplePath: program.examplePath,
       typescript: program.typescript,
+      experimentalApp: program.experimentalApp,
     })
   } catch (reason) {
     if (!(reason instanceof DownloadError)) {
@@ -158,6 +166,7 @@ async function run(): Promise<void> {
       appPath: resolvedProjectPath,
       packageManager,
       typescript: program.typescript,
+      experimentalApp: program.experimentalApp,
     })
   }
 }

packages/create-next-app/templates/experimental-app/README-template.md

@@ -0,0 +1,34 @@
+This is a [Next.js](https://nextjs.org/) project bootstrapped with [`create-next-app`](https://github.com/vercel/next.js/tree/canary/packages/create-next-app).
+
+## Getting Started
+
+First, run the development server:
+
+```bash
+npm run dev
+# or
+yarn dev
+```
+
+Open [http://localhost:3000](http://localhost:3000) with your browser to see the result.
+
+You can start editing the page by modifying `app/page.tsx`. The page auto-updates as you edit the file.
+
+[API routes](https://nextjs.org/docs/api-routes/introduction) can be accessed on [http://localhost:3000/api/hello](http://localhost:3000/api/hello). This endpoint can be edited in `pages/api/hello.ts`.
+
+The `pages/api` directory is mapped to `/api/*`. Files in this directory are treated as [API routes](https://nextjs.org/docs/api-routes/introduction) instead of React pages.
+
+## Learn More
+
+To learn more about Next.js, take a look at the following resources:
+
+- [Next.js Documentation](https://nextjs.org/docs) - learn about Next.js features and API.
+- [Learn Next.js](https://nextjs.org/learn) - an interactive Next.js tutorial.
+
+You can check out [the Next.js GitHub repository](https://github.com/vercel/next.js/) - your feedback and contributions are welcome!
+
+## Deploy on Vercel
+
+The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
+
+Check out our [Next.js deployment documentation](https://nextjs.org/docs/deployment) for more details.

packages/create-next-app/templates/experimental-app/app/layout.tsx

@@ -0,0 +1,10 @@
+export default function RootLayout({ children }) {
+  return (
+    <html lang="en">
+      <head>
+        <title>Create Next App</title>
+      </head>
+      <body>{children}</body>
+    </html>
+  )
+}

packages/create-next-app/templates/experimental-app/app/page.tsx

@@ -0,0 +1,7 @@
+export default function Page() {
+  return (
+    <h1>
+      Welcome to <a href="https://nextjs.org">Next.js!</a>
+    </h1>
+  )
+}

packages/create-next-app/templates/experimental-app/eslintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": "next/core-web-vitals"
+}

packages/create-next-app/templates/experimental-app/gitignore

@@ -0,0 +1,36 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+.pnpm-debug.log*
+
+# local env files
+.env*.local
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo
+next-env.d.ts

packages/create-next-app/templates/experimental-app/next-env.d.ts

@@ -0,0 +1,5 @@
+/// <reference types="next" />
+/// <reference types="next/image-types/global" />
+
+// NOTE: This file should not be edited
+// see https://nextjs.org/docs/basic-features/typescript for more information.

packages/create-next-app/templates/experimental-app/next.config.js

@@ -0,0 +1,8 @@
+/** @type {import('next').NextConfig} */
+const nextConfig = {
+  experimental: {
+    appDir: true,
+  },
+}
+
+module.exports = nextConfig

packages/create-next-app/templates/experimental-app/pages/api/hello.ts

@@ -0,0 +1,13 @@
+// Next.js API route support: https://nextjs.org/docs/api-routes/introduction
+import type { NextApiRequest, NextApiResponse } from 'next'
+
+type Data = {
+  name: string
+}
+
+export default function handler(
+  req: NextApiRequest,
+  res: NextApiResponse<Data>
+) {
+  res.status(200).json({ name: 'John Doe' })
+}

packages/create-next-app/templates/experimental-app/tsconfig.json

@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ]
+  },
+  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
+  "exclude": ["node_modules"]
+}

packages/create-next-app/templates/typescript/pages/_app.tsx

@@ -1,8 +1,6 @@
 import '../styles/globals.css'
 import type { AppProps } from 'next/app'
 
-function MyApp({ Component, pageProps }: AppProps) {
+export default function App({ Component, pageProps }: AppProps) {
   return <Component {...pageProps} />
 }
-
-export default MyApp

packages/create-next-app/templates/typescript/pages/index.tsx

@@ -1,9 +1,8 @@
-import type { NextPage } from 'next'
 import Head from 'next/head'
 import Image from 'next/image'
 import styles from '../styles/Home.module.css'
 
-const Home: NextPage = () => {
+export default function Home() {
   return (
     <div className={styles.container}>
       <Head>
@@ -70,5 +69,3 @@ const Home: NextPage = () => {
     </div>
   )
 }
-
-export default Home