Ensure CNA install succeeds with npm and example flags (#25267)

* Ensure CNA install succeeds with npm and example flags

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

@@ -30,7 +30,7 @@ export function install(
   /**
    * NPM-specific command-line flags.
    */
-  const npmFlags: string[] = ['--logLevel', 'error']
+  const npmFlags: string[] = []
   /**
    * Yarn-specific command-line flags.
    */

test/integration/create-next-app/index.test.js

@@ -17,7 +17,7 @@ async function usingTempDir(fn, options) {
   const folder = path.join(os.tmpdir(), Math.random().toString(36).substring(2))
   await fs.mkdirp(folder, options)
   try {
-    return await fn(folder)
+    await fn(folder)
   } finally {
     await fs.remove(folder)
   }
@@ -52,6 +52,9 @@ describe('create next app', () => {
         expect(
           fs.existsSync(path.join(cwd, projectName, 'pages/index.js'))
         ).toBeTruthy()
+        expect(
+          fs.existsSync(path.join(cwd, projectName, 'node_modules/next'))
+        ).toBe(true)
       })
     })
   }
@@ -88,6 +91,9 @@ describe('create next app', () => {
       expect(
         fs.existsSync(path.join(cwd, projectName, '.gitignore'))
       ).toBeTruthy()
+      expect(
+        fs.existsSync(path.join(cwd, projectName, 'node_modules/next'))
+      ).toBe(true)
     })
   })
 
@@ -115,6 +121,9 @@ describe('create next app', () => {
       expect(
         fs.existsSync(path.join(cwd, projectName, 'next-env.d.ts'))
       ).toBeTruthy()
+      expect(
+        fs.existsSync(path.join(cwd, projectName, 'node_modules/next'))
+      ).toBe(true)
       // check we copied default `.gitignore`
       expect(
         fs.existsSync(path.join(cwd, projectName, '.gitignore'))
@@ -154,6 +163,9 @@ describe('create next app', () => {
       expect(
         fs.existsSync(path.join(cwd, projectName, '.gitignore'))
       ).toBeTruthy()
+      expect(
+        fs.existsSync(path.join(cwd, projectName, 'node_modules/next'))
+      ).toBe(true)
     })
   })
 
@@ -177,6 +189,9 @@ describe('create next app', () => {
       expect(
         fs.existsSync(path.join(cwd, projectName, '.gitignore'))
       ).toBeTruthy()
+      expect(
+        fs.existsSync(path.join(cwd, projectName, 'node_modules/next'))
+      ).toBe(true)
     })
   })
 
@@ -206,6 +221,9 @@ describe('create next app', () => {
       expect(
         fs.existsSync(path.join(cwd, projectName, '.gitignore'))
       ).toBeTruthy()
+      expect(
+        fs.existsSync(path.join(cwd, projectName, 'node_modules/next'))
+      ).toBe(true)
     })
   })
 
@@ -248,6 +266,9 @@ describe('create next app', () => {
       expect(
         fs.existsSync(path.join(cwd, projectName, '.gitignore'))
       ).toBeTruthy()
+      expect(
+        fs.existsSync(path.join(cwd, projectName, 'node_modules/next'))
+      ).toBe(true)
     })
   })
 
@@ -283,7 +304,12 @@ describe('create next app', () => {
       const res = await run(['.'], { cwd })
       expect(res.exitCode).toBe(0)
 
-      const files = ['package.json', 'pages/index.js', '.gitignore']
+      const files = [
+        'package.json',
+        'pages/index.js',
+        '.gitignore',
+        'node_modules/next',
+      ]
       files.forEach((file) =>
         expect(fs.existsSync(path.join(cwd, file))).toBeTruthy()
       )
@@ -296,7 +322,12 @@ describe('create next app', () => {
       const res = await run([], { cwd, input: `${projectName}\n` })
       expect(res.exitCode).toBe(0)
 
-      const files = ['package.json', 'pages/index.js', '.gitignore']
+      const files = [
+        'package.json',
+        'pages/index.js',
+        '.gitignore',
+        'node_modules/next',
+      ]
       files.forEach((file) =>
         expect(fs.existsSync(path.join(cwd, projectName, file))).toBeTruthy()
       )
@@ -314,6 +345,34 @@ describe('create next app', () => {
         'pages/index.js',
         '.gitignore',
         'package-lock.json',
+        'node_modules/next',
+      ]
+      files.forEach((file) =>
+        expect(fs.existsSync(path.join(cwd, projectName, file))).toBeTruthy()
+      )
+    })
+  })
+
+  it('should use npm as the package manager on supplying --use-npm with example', async () => {
+    await usingTempDir(async (cwd) => {
+      const projectName = 'use-npm'
+      const res = await run(
+        [
+          projectName,
+          '--use-npm',
+          '--example',
+          'https://github.com/vercel/next-learn-starter/tree/master/learn-starter',
+        ],
+        { cwd }
+      )
+      expect(res.exitCode).toBe(0)
+
+      const files = [
+        'package.json',
+        'pages/index.js',
+        '.gitignore',
+        'package-lock.json',
+        'node_modules/next',
       ]
       files.forEach((file) =>
         expect(fs.existsSync(path.join(cwd, projectName, file))).toBeTruthy()