import { existsSync } from 'fs'
import { readFile } from 'fs/promises'
import { join } from 'path'
import { run, useTempDir } from './utils'
describe('create-next-app ESLint configuration', () => {
let nextTgzFilename: string
beforeAll(() => {
if (!process.env.NEXT_TEST_PKG_PATHS) {
throw new Error('This test needs to be run with `node run-tests.js`.')
}
const pkgPaths = new Map<string, string>(
JSON.parse(process.env.NEXT_TEST_PKG_PATHS)
)
nextTgzFilename = pkgPaths.get('next')
})
it('should generate eslint.config.mjs for TypeScript project with ESLint', async () => {
await useTempDir(async (cwd) => {
const projectName = 'test-eslint-ts'
const { exitCode } = await run(
[
projectName,
'--ts',
'--eslint',
'--no-tailwind',
'--no-src-dir',
'--no-react-compiler',
'--no-agents-md',
'--app',
'--no-import-alias',
'--skip-install',
],
nextTgzFilename,
{ cwd }
)
expect(exitCode).toBe(0)
const projectDir = join(cwd, projectName)
// Should have eslint.config.mjs
expect(existsSync(join(projectDir, 'eslint.config.mjs'))).toBe(true)
// Should NOT have biome.json
expect(existsSync(join(projectDir, 'biome.json'))).toBe(false)
// Check eslint.config.mjs content
const eslintConfig = await readFile(
join(projectDir, 'eslint.config.mjs'),
'utf8'
)
expect(eslintConfig).toContain('next/core-web-vitals')
expect(eslintConfig).toContain('next/typescript')
// Check package.json scripts
const packageJson = JSON.parse(
await readFile(join(projectDir, 'package.json'), 'utf8')
)
expect(packageJson.scripts.lint).toBe('eslint')
expect(packageJson.devDependencies.eslint).toBeTruthy()
expect(packageJson.devDependencies['eslint-config-next']).toBeTruthy()
})
})
it('should generate eslint.config.mjs for JavaScript project with ESLint', async () => {
await useTempDir(async (cwd) => {
const projectName = 'test-eslint-js'
const { exitCode } = await run(
[
projectName,
'--js',
'--eslint',
'--no-tailwind',
'--no-src-dir',
'--no-react-compiler',
'--no-agents-md',
'--app',
'--no-import-alias',
'--skip-install',
],
nextTgzFilename,
{ cwd }
)
expect(exitCode).toBe(0)
const projectDir = join(cwd, projectName)
// Should have eslint.config.mjs
expect(existsSync(join(projectDir, 'eslint.config.mjs'))).toBe(true)
// Check eslint.config.mjs content for JS project
const eslintConfig = await readFile(
join(projectDir, 'eslint.config.mjs'),
'utf8'
)
expect(eslintConfig).toContain('next/core-web-vitals')
expect(eslintConfig).not.toContain('next/typescript')
// Check package.json scripts
const packageJson = JSON.parse(
await readFile(join(projectDir, 'package.json'), 'utf8')
)
expect(packageJson.scripts.lint).toBe('eslint')
expect(packageJson.devDependencies.eslint).toBeTruthy()
expect(packageJson.devDependencies['eslint-config-next']).toBeTruthy()
})
})
})