feat: enable @typescript-eslint/recommended in create-next-app --typescript (#52845)

JoshuaKGoldberg · eps1lon · lubieowoce · commit c021c2f7f724 · 2024-09-02T18:25:42.000+02:00
Co-authored-by: eps1lon &lt;sebastian.silbermann@vercel.com&gt;
diff --git a/docs/02-app/01-building-your-application/07-configuring/02-eslint.mdx b/docs/02-app/01-building-your-application/07-configuring/02-eslint.mdx
@@ -202,6 +202,19 @@ The `next/core-web-vitals` rule set is enabled when `next lint` is run for the f
 
 > The `next/core-web-vitals` entry point is automatically included for new applications built with [Create Next App](/docs/app/api-reference/create-next-app).
 
+### TypeScript
+
+In addition to the Next.js ESLint rules, `create-next-app --typescript` will also add TypeScript-specific lint rules with `next/typescript` to your config:
+
+```json filename=".eslintrc.json"
+{
+  "extends": ["next/core-web-vitals", "next/typescript"]
+}
+```
+
+Those rules are based on [`plugin:@typescript-eslint/recommended`](https://typescript-eslint.io/linting/configs#recommended).
+See [typescript-eslint > Configs](https://typescript-eslint.io/linting/configs) for more details.
+
 ## Usage With Other Tools
 
 ### Prettier
diff --git a/examples/with-temporal/package.json b/examples/with-temporal/package.json
@@ -24,8 +24,8 @@
     "@types/node-fetch": "^3.0.3",
     "@types/react": "^17.0.2",
     "@types/react-dom": "^17.0.1",
-    "@typescript-eslint/eslint-plugin": "^5.3.0",
-    "@typescript-eslint/parser": "^5.3.0",
+    "@typescript-eslint/eslint-plugin": "^6.1.0",
+    "@typescript-eslint/parser": "^6.1.0",
     "cross-env": "^7.0.3",
     "nodemon": "^2.0.12",
     "ts-node": "^10.2.1",
diff --git a/packages/create-next-app/templates/app-tw/ts/eslintrc.json b/packages/create-next-app/templates/app-tw/ts/eslintrc.json
@@ -1,3 +1,3 @@
 {
-  "extends": "next/core-web-vitals"
+  "extends": ["next/core-web-vitals", "next/typescript"]
 }
diff --git a/packages/create-next-app/templates/app/ts/eslintrc.json b/packages/create-next-app/templates/app/ts/eslintrc.json
@@ -1,3 +1,3 @@
 {
-  "extends": "next/core-web-vitals"
+  "extends": ["next/core-web-vitals", "next/typescript"]
 }
diff --git a/packages/create-next-app/templates/default-tw/ts/eslintrc.json b/packages/create-next-app/templates/default-tw/ts/eslintrc.json
@@ -1,3 +1,3 @@
 {
-  "extends": "next/core-web-vitals"
+  "extends": ["next/core-web-vitals", "next/typescript"]
 }
diff --git a/packages/create-next-app/templates/default/ts/eslintrc.json b/packages/create-next-app/templates/default/ts/eslintrc.json
@@ -1,3 +1,3 @@
 {
-  "extends": "next/core-web-vitals"
+  "extends": ["next/core-web-vitals", "next/typescript"]
 }
diff --git a/packages/eslint-config-next/index.js b/packages/eslint-config-next/index.js
@@ -30,12 +30,13 @@ sortedPaths.push(...keptPaths)
 
 const hookPropertyMap = new Map(
   [
-    ['eslint-plugin-import', 'eslint-plugin-import'],
-    ['eslint-plugin-react', 'eslint-plugin-react'],
-    ['eslint-plugin-jsx-a11y', 'eslint-plugin-jsx-a11y'],
-  ].map(([request, replacement]) => [
+    '@typescript-eslint/eslint-plugin',
+    'eslint-plugin-import',
+    'eslint-plugin-react',
+    'eslint-plugin-jsx-a11y',
+  ].map((request) => [
     request,
-    require.resolve(replacement, { paths: sortedPaths }),
+    require.resolve(request, { paths: sortedPaths }),
   ])
 )
 
@@ -96,10 +97,6 @@ module.exports = {
       parser: '@typescript-eslint/parser',
       parserOptions: {
         sourceType: 'module',
-        ecmaFeatures: {
-          jsx: true,
-        },
-        warnOnUnsupportedTypeScriptVersion: true,
       },
     },
   ],
diff --git a/packages/eslint-config-next/package.json b/packages/eslint-config-next/package.json
@@ -12,6 +12,7 @@
   "dependencies": {
     "@next/eslint-plugin-next": "14.2.7",
     "@rushstack/eslint-patch": "^1.3.3",
+    "@typescript-eslint/eslint-plugin": "^5.4.2 || ^6.0.0 || 7.0.0 - 7.2.0",
     "@typescript-eslint/parser": "^5.4.2 || ^6.0.0 || 7.0.0 - 7.2.0",
     "eslint-import-resolver-node": "^0.3.6",
     "eslint-import-resolver-typescript": "^3.5.2",
diff --git a/packages/eslint-config-next/typescript.js b/packages/eslint-config-next/typescript.js
@@ -0,0 +1,3 @@
+module.exports = {
+  extends: ['plugin:@typescript-eslint/recommended'],
+}
diff --git a/packages/next/src/lib/constants.ts b/packages/next/src/lib/constants.ts
@@ -78,26 +78,6 @@ export const SSG_FALLBACK_EXPORT_ERROR = `Pages with \`fallback\` enabled in \`g
 
 export const ESLINT_DEFAULT_DIRS = ['app', 'pages', 'components', 'lib', 'src']
 
-export const ESLINT_PROMPT_VALUES = [
-  {
-    title: 'Strict',
-    recommended: true,
-    config: {
-      extends: 'next/core-web-vitals',
-    },
-  },
-  {
-    title: 'Base',
-    config: {
-      extends: 'next',
-    },
-  },
-  {
-    title: 'Cancel',
-    config: null,
-  },
-]
-
 export const SERVER_RUNTIME: Record<string, ServerRuntime> = {
   edge: 'edge',
   experimentalEdge: 'experimental-edge',
diff --git a/packages/next/src/lib/eslint/getESLintPromptValues.ts b/packages/next/src/lib/eslint/getESLintPromptValues.ts
@@ -0,0 +1,32 @@
+import findUp from 'next/dist/compiled/find-up'
+
+export const getESLintStrictValue = async (cwd: string) => {
+  const tsConfigLocation = await findUp('tsconfig.json', { cwd })
+  const hasTSConfig = tsConfigLocation !== undefined
+
+  return {
+    title: 'Strict',
+    recommended: true,
+    config: {
+      extends: hasTSConfig
+        ? ['next/core-web-vitals', 'next/typescript']
+        : 'next/core-web-vitals',
+    },
+  }
+}
+
+export const getESLintPromptValues = async (cwd: string) => {
+  return [
+    await getESLintStrictValue(cwd),
+    {
+      title: 'Base',
+      config: {
+        extends: 'next',
+      },
+    },
+    {
+      title: 'Cancel',
+      config: null,
+    },
+  ]
+}
diff --git a/packages/next/src/lib/eslint/runLintCheck.ts b/packages/next/src/lib/eslint/runLintCheck.ts
@@ -12,7 +12,6 @@ import { writeDefaultConfig } from './writeDefaultConfig'
 import { hasEslintConfiguration } from './hasEslintConfiguration'
 import { writeOutputFile } from './writeOutputFile'
 
-import { ESLINT_PROMPT_VALUES } from '../constants'
 import { findPagesDir } from '../find-pages-dir'
 import { installDependencies } from '../install-dependencies'
 import { hasNecessaryDependencies } from '../has-necessary-dependencies'
@@ -21,6 +20,10 @@ import * as Log from '../../build/output/log'
 import type { EventLintCheckCompleted } from '../../telemetry/events/build'
 import isError, { getProperError } from '../is-error'
 import { getPkgManager } from '../helpers/get-pkg-manager'
+import {
+  getESLintStrictValue,
+  getESLintPromptValues,
+} from './getESLintPromptValues'
 
 type Config = {
   plugins: string[]
@@ -44,7 +47,7 @@ const requiredPackages = [
   },
 ]
 
-async function cliPrompt(): Promise<{ config?: any }> {
+async function cliPrompt(cwd: string): Promise<{ config?: any }> {
   console.log(
     bold(
       `${cyan(
@@ -58,7 +61,7 @@ async function cliPrompt(): Promise<{ config?: any }> {
       await Promise.resolve(require('next/dist/compiled/cli-select'))
     ).default
     const { value } = await cliSelect({
-      values: ESLINT_PROMPT_VALUES,
+      values: await getESLintPromptValues(cwd),
       valueRenderer: (
         {
           title,
@@ -355,10 +358,8 @@ export async function runLintCheck(
       } else {
         // Ask user what config they would like to start with for first time "next lint" setup
         const { config: selectedConfig } = strict
-          ? ESLINT_PROMPT_VALUES.find(
-              (opt: { title: string }) => opt.title === 'Strict'
-            )!
-          : await cliPrompt()
+          ? await getESLintStrictValue(baseDir)
+          : await cliPrompt(baseDir)
 
         if (selectedConfig == null) {
           // Show a warning if no option is selected in prompt
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
diff --git a/test/integration/eslint/test/next-lint.test.js b/test/integration/eslint/test/next-lint.test.js
@@ -120,7 +120,9 @@ describe('Next Lint', () => {
         'We created the .eslintrc.json file for you and included your selected configuration'
       )
       expect(eslintrcJson).toMatchObject({ extends: 'next/core-web-vitals' })
+    })
 
+    test('creates .eslintrc.json file with a default app router configuration', async () => {
       // App Router
       const { stdout: appStdout, eslintrcJson: appEslintrcJson } =
         await nextLintTemp(null, true)
diff --git a/test/production/eslint/test/__snapshots__/next-build-and-lint.test.ts.snap b/test/production/eslint/test/__snapshots__/next-build-and-lint.test.ts.snap
diff --git a/test/production/eslint/test/next-build-and-lint.test.ts b/test/production/eslint/test/next-build-and-lint.test.ts

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,3 @@`
`1`	`1`	`{`
`2`		`- "extends": "next/core-web-vitals"`
	`2`	`+ "extends": ["next/core-web-vitals", "next/typescript"]`
`3`	`3`	`}`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+module.exports = {`
	`2`	`+ extends: ['plugin:@typescript-eslint/recommended'],`
	`3`	`+}`