some change for db file

.devcontainer/devcontainer-lock.json

@@ -16,4 +16,4 @@
       "integrity": "sha256:0c55e65f2e3df736e478f26ee4d5ed41bae6b54dac1318c443e31444c8ed283c"
     }
   }
-}
+}

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

@@ -1,6 +1,7 @@
 /* eslint-disable import/no-extraneous-dependencies */
+
 import retry from 'async-retry'
-import { copyFileSync, existsSync, mkdirSync } from 'node:fs'
+import { copyFileSync, existsSync, mkdirSync, writeFileSync } from 'node:fs'
 import { basename, dirname, join, resolve } from 'node:path'
 import { cyan, green, red } from 'picocolors'
 import type { RepoInfo } from './helpers/examples'
@@ -35,6 +36,7 @@ export async function createApp({
   biome,
   app,
   srcDir,
+  mongodb,
   importAlias,
   skipInstall,
   empty,
@@ -53,6 +55,7 @@ export async function createApp({
   biome: boolean
   app: boolean
   srcDir: boolean
+  mongodb?: boolean
   importAlias: string
   skipInstall: boolean
   empty: boolean
@@ -254,7 +257,62 @@ export async function createApp({
       reactCompiler,
     })
   }
+  // --- MongoDB Logic Start ---
+  // --- MongoDB Change Start ---
+  if (mongodb) {
+    const dbFolderPath = join(root, 'lib')
+    const dbFilePath = join(dbFolderPath, typescript ? 'db.ts' : 'db.js')
+
+    if (!existsSync(dbFolderPath)) {
+      mkdirSync(dbFolderPath, { recursive: true })
+    }
+
+    const dbCode = `import { MongoClient } from 'mongodb'
+
+if (!process.env.MONGODB_URI) {
+  throw new Error('Invalid/Missing environment variable: "MONGODB_URI"')
+}
+
+const uri = process.env.MONGODB_URI
+const options = {}
+
+let client: MongoClient
+let clientPromise: Promise<MongoClient>
 
+if (process.env.NODE_ENV === 'development') {
+  let globalWithMongo = global as typeof globalThis & {
+    _mongoClientPromise?: Promise<MongoClient>
+  }
+  if (!globalWithMongo._mongoClientPromise) {
+    client = new MongoClient(uri, options)
+    globalWithMongo._mongoClientPromise = client.connect()
+  }
+  clientPromise = globalWithMongo._mongoClientPromise
+} else {
+  client = new MongoClient(uri, options)
+  clientPromise = client.connect()
+}
+
+export default clientPromise`
+
+    writeFileSync(dbFilePath, dbCode)
+
+    // Safely append to .env.local with proper casting
+    const fs = require('node:fs') as typeof import('node:fs')
+    const envPath = join(root, '.env.local')
+    const envContent = `\nMONGODB_URI=mongodb+srv://<username>:<password>@cluster.mongodb.net/myDatabase?retryWrites=true&w=majority\n`
+
+    if (fs.existsSync(envPath)) {
+      fs.appendFileSync(envPath, envContent)
+    } else {
+      fs.writeFileSync(envPath, envContent)
+    }
+
+    console.log(
+      `${green('Added')} MongoDB connection utility in ${cyan('lib/db.' + (typescript ? 'ts' : 'js'))}`
+    )
+  }
+  // --- MongoDB Logic End ---
   if (disableGit) {
     console.log('Skipping git initialization.')
     console.log()

packages/create-next-app/index.ts

@@ -1,9 +1,10 @@
 #!/usr/bin/env node
 /* eslint-disable import/no-extraneous-dependencies */
+import { existsSync } from 'node:fs'
+import { isFolderEmpty } from './helpers/is-folder-empty'
 import ciInfo from 'ci-info'
 import { Command } from 'commander'
 import Conf from 'conf'
-import { existsSync } from 'node:fs'
 import { basename, resolve } from 'node:path'
 import { blue, bold, cyan, green, red, yellow } from 'picocolors'
 import type { InitialReturnValue } from 'prompts'
@@ -12,7 +13,6 @@ import updateCheck from 'update-check'
 import { createApp, DownloadError } from './create-app'
 import type { PackageManager } from './helpers/get-pkg-manager'
 import { getPkgManager } from './helpers/get-pkg-manager'
-import { isFolderEmpty } from './helpers/is-folder-empty'
 import { validateNpmName } from './helpers/validate-pkg'
 import packageJson from './package.json'
 import { Bundler } from './templates'
@@ -109,6 +109,7 @@ const program = new Command(packageJson.name)
 `
   )
   .option('--disable-git', `Skip initializing a git repository.`)
+  .option('--mongodb', 'Initialize with MongoDB connection logic.')
   .action((name) => {
     // Commander does not implicitly support negated options. When they are used
     // by the user they will be interpreted as the positional argument (name) in
@@ -188,9 +189,11 @@ async function run(): Promise<void> {
     )
     process.exit(1)
   }
-
   const appPath = resolve(projectPath)
   const appName = basename(appPath)
+  if (existsSync(appPath) && !isFolderEmpty(appPath, appName)) {
+    process.exit(1)
+  }
 
   const validation = validateNpmName(appName)
   if (!validation.valid) {
@@ -212,10 +215,7 @@ async function run(): Promise<void> {
     )
     process.exit(1)
   }
-
-  if (existsSync(appPath) && !isFolderEmpty(appPath, appName)) {
-    process.exit(1)
-  }
+  // Inside the !example block where displayConfig is defined
 
   const example = typeof opts.example === 'string' && opts.example.trim()
   const preferences = (conf.get('preferences') || {}) as Record<
@@ -234,6 +234,7 @@ async function run(): Promise<void> {
     const defaults: typeof preferences = {
       typescript: true,
       eslint: false,
+      mongodb: false,
       linter: 'eslint',
       tailwind: true,
       app: true,
@@ -260,6 +261,7 @@ async function run(): Promise<void> {
       { key: 'tailwind', values: { true: 'Tailwind CSS' } },
       { key: 'srcDir', values: { true: 'src/ dir' } },
       { key: 'app', values: { true: 'App Router', false: 'Pages Router' } },
+      { key: 'mongodb', values: { true: 'MongoDB', false: '' } },
     ]
 
     // Helper to format settings for display based on displayConfig
@@ -442,9 +444,28 @@ async function run(): Promise<void> {
               getPrefOrDefault('linter') as keyof typeof linterIndexMap
             ],
         })
-
+        // MongoDB Prompt
+        if (!opts.mongodb && !args.includes('--no-mongodb') && !opts.api) {
+          if (skipPrompt) {
+            opts.mongodb = getPrefOrDefault('mongodb')
+          } else {
+            const mongoLabel = blue('MongoDB')
+            const { mongodb } = await prompts({
+              onState: onPromptState,
+              type: 'toggle',
+              name: 'mongodb',
+              message: `Would you like to use ${mongoLabel} connection?`,
+              initial: getPrefOrDefault('mongodb'),
+              active: 'Yes',
+              inactive: 'No',
+            })
+            opts.mongodb = Boolean(mongodb)
+            preferences.mongodb = Boolean(mongodb)
+          }
+        }
         opts.eslint = linter === 'eslint'
         opts.biome = linter === 'biome'
+
         preferences.linter = linter
 
         // Keep backwards compatibility with old eslint preference
@@ -606,6 +627,7 @@ async function run(): Promise<void> {
       examplePath: opts.examplePath,
       typescript: opts.typescript,
       tailwind: opts.tailwind,
+      mongodb: opts.mongodb,
       eslint: opts.eslint,
       biome: opts.biome,
       app: opts.app,
@@ -642,6 +664,7 @@ async function run(): Promise<void> {
       typescript: opts.typescript,
       eslint: opts.eslint,
       biome: opts.biome,
+      mongodb: opts.mongodb,
       tailwind: opts.tailwind,
       app: opts.app,
       srcDir: opts.srcDir,