ESLint: More updates and bug fixes

packages/next/cli/next-lint.ts

@@ -5,23 +5,65 @@ import { resolve, join } from 'path'
 import chalk from 'chalk'
 
 import { cliCommand } from '../bin/next'
+import { ESLINT_DEFAULT_DIRS } from '../lib/constants'
 import { runLintCheck } from '../lib/eslint/runLintCheck'
 import { printAndExit } from '../server/lib/utils'
 
+const eslintOptions = (args: arg.Spec) => ({
+  overrideConfigFile: args['--config'] || null,
+  extensions: args['--ext'] ?? ['.js', '.jsx', '.ts', '.tsx'],
+  resolvePluginsRelativeTo: args['--resolve-plugins-relative-to'] || null,
+  rulePaths: args['--rulesdir'] ?? [],
+  fix: args['--fix'] ?? false,
+  fixTypes: args['--fix-type'] ?? null,
+  ignorePath: args['--ignore-path'] || null,
+  ignore: !Boolean(args['--no-ignore']),
+  allowInlineConfig: !Boolean(args['--no-inline-config']),
+  reportUnusedDisableDirectives:
+    args['--report-unused-disable-directives'] || null,
+  cache: args['--cache'] ?? false,
+  cacheLocation: args['--cache-location'] || '.eslintcache',
+  cacheStrategy: args['--cache-strategy'] || 'metadata',
+  errorOnUnmatchedPattern: !Boolean(args['--no-error-on-unmatched-pattern']),
+})
+
 const nextLint: cliCommand = (argv) => {
   const validArgs: arg.Spec = {
     // Types
     '--help': Boolean,
+    '--base-dir': String,
     '--dir': [String],
 
     // Aliases
     '-h': '--help',
+    '-b': '--base-dir',
     '-d': '--dir',
   }
 
+  const validEslintArgs: arg.Spec = {
+    // Types
+    '--config': String,
+    '--ext': [String],
+    '--resolve-plugins-relative-to': String,
+    '--rulesdir': [String],
+    '--fix': Boolean,
+    '--fix-type': [String],
+    '--ignore-path': String,
+    '--no-ignore': Boolean,
+    '--no-inline-config': Boolean,
+    '--report-unused-disable-directives': String,
+    '--cache': Boolean,
+    '--cache-location': String,
+    '--cache-strategy': String,
+    '--no-error-on-unmatched-pattern': Boolean,
+
+    // Aliases
+    '-c': '--config',
+  }
+
   let args: arg.Result<arg.Spec>
   try {
-    args = arg(validArgs, { argv })
+    args = arg({ ...validArgs, ...validEslintArgs }, { argv })
   } catch (error) {
     if (error.code === 'ARG_UNKNOWN_OPTION') {
       return printAndExit(error.message, 1)
@@ -37,14 +79,41 @@ const nextLint: cliCommand = (argv) => {
 
       Usage
         $ next lint <baseDir> [options]
-
+      
       <baseDir> represents the directory of the Next.js application.
       If no directory is provided, the current directory will be used.
 
       Options
-      -h - list this help
-      -d - set directory, or directories, to run ESLint (defaults to only 'pages')
-    `,
+        Basic configuration:
+          -h, --help                     List this help
+          -d, --dir Array                Set directory, or directories, to run ESLint - default: 'pages', 'components', and 'lib'
+          -c, --config path::String      Use this configuration file, overriding all other config options
+          --ext [String]                 Specify JavaScript file extensions - default: .js, .jsx, .ts, .tsx
+          --resolve-plugins-relative-to path::String  A folder where plugins should be resolved from, CWD by default
+
+        Specifying rules:
+          --rulesdir [path::String]      Use additional rules from this directory
+
+        Fixing problems:
+          --fix                          Automatically fix problems
+          --fix-type Array               Specify the types of fixes to apply (problem, suggestion, layout)
+
+        Ignoring files:
+          --ignore-path path::String     Specify path of ignore file
+          --no-ignore                    Disable use of ignore files and patterns
+
+        Inline configuration comments:
+          --no-inline-config             Prevent comments from changing config or rules
+          --report-unused-disable-directives  Adds reported errors for unused eslint-disable directives ("error" | "warn" | "off")
+
+        Caching:
+          --cache                        Only check changed files - default: false
+          --cache-location path::String  Path to the cache file or directory - default: .eslintcache
+          --cache-strategy String        Strategy to use for detecting changed files - either: metadata or content - default: metadata
+
+        Miscellaneous:
+          --no-error-on-unmatched-pattern  Prevent errors when pattern is unmatched - default: false
+          `,
       0
     )
   }
@@ -57,7 +126,7 @@ const nextLint: cliCommand = (argv) => {
   }
 
   const dirs: string[] = args['--dir']
-  const lintDirs = (dirs ?? ['pages', 'components', 'lib']).reduce(
+  const lintDirs = (dirs ?? ESLINT_DEFAULT_DIRS).reduce(
     (res: string[], d: string) => {
       const currDir = join(baseDir, d)
       if (!existsSync(currDir)) return res
@@ -67,7 +136,7 @@ const nextLint: cliCommand = (argv) => {
     []
   )
 
-  runLintCheck(baseDir, lintDirs)
+  runLintCheck(baseDir, lintDirs, false, eslintOptions(args))
     .then((results) => {
       if (results) {
         console.log(results)

packages/next/lib/constants.ts

@@ -48,3 +48,12 @@ export const GSSP_COMPONENT_MEMBER_ERROR = `can not be attached to a page's comp
 export const NON_STANDARD_NODE_ENV = `You are using a non-standard "NODE_ENV" value in your environment. This creates inconsistencies in the project and is strongly advised against. Read more: https://nextjs.org/docs/messages/non-standard-node-env`
 
 export const SSG_FALLBACK_EXPORT_ERROR = `Pages with \`fallback\` enabled in \`getStaticPaths\` can not be exported. See more info here: https://nextjs.org/docs/messages/ssg-fallback-true-export`
+
+export const ESLINT_DEFAULT_DIRS = [
+  'pages',
+  'components',
+  'lib',
+  'src/pages',
+  'src/components',
+  'src/lib',
+]

packages/next/lib/eslint/runLintCheck.ts

@@ -1,13 +1,14 @@
 import { promises as fs } from 'fs'
 import chalk from 'chalk'
+import path from 'path'
 
 import findUp from 'next/dist/compiled/find-up'
 import semver from 'next/dist/compiled/semver'
 import * as CommentJson from 'next/dist/compiled/comment-json'
 
 import { formatResults } from './customFormatter'
 import { writeDefaultConfig } from './writeDefaultConfig'
-import { findPagesDir } from '../find-pages-dir'
+import { existsSync, findPagesDir } from '../find-pages-dir'
 import { CompileError } from '../compile-error'
 import {
   hasNecessaryDependencies,
@@ -21,16 +22,13 @@ type Config = {
   rules: { [key: string]: Array<number | string> }
 }
 
-const linteableFiles = (dir: string) => {
-  return `${dir}/**/*.{${['jsx', 'js', 'ts', 'tsx'].join(',')}}`
-}
-
 async function lint(
   deps: NecessaryDependencies,
   baseDir: string,
   lintDirs: string[],
   eslintrcFile: string | null,
-  pkgJsonPath: string | null
+  pkgJsonPath: string | null,
+  eslintOptions: any = null
 ): Promise<string | null> {
   // Load ESLint after we're sure it exists:
   const mod = await import(deps.resolved)
@@ -41,23 +39,23 @@ async function lint(
     const eslintVersion: string | undefined = mod?.CLIEngine?.version
 
     if (!eslintVersion || semver.lt(eslintVersion, '7.0.0')) {
-      Log.error(
-        `Your project has an older version of ESLint installed${
-          eslintVersion ? ' (' + eslintVersion + ')' : ''
-        }. Please upgrade to ESLint version 7 or later`
-      )
-      return null
+      return `${chalk.red(
+        'error'
+      )} - Your project has an older version of ESLint installed${
+        eslintVersion ? ' (' + eslintVersion + ')' : ''
+      }. Please upgrade to ESLint version 7 or later`
     }
 
-    Log.error(
-      `ESLint class not found. Please upgrade to ESLint version 7 or later`
-    )
-    return null
+    return `${chalk.red(
+      'error'
+    )} - ESLint class not found. Please upgrade to ESLint version 7 or later`
   }
 
   let options: any = {
     useEslintrc: true,
     baseConfig: {},
+    extensions: ['.js', '.jsx', '.ts', '.tsx'],
+    ...eslintOptions,
   }
   let eslint = new ESLint(options)
 
@@ -101,18 +99,21 @@ async function lint(
       eslint = new ESLint(options)
     }
   }
+  const results = await eslint.lintFiles(lintDirs)
+  if (options.fix) await ESLint.outputFixes(results)
 
-  const results = await eslint.lintFiles(lintDirs.map(linteableFiles))
   if (ESLint.getErrorResults(results)?.length > 0) {
     throw new CompileError(await formatResults(baseDir, results))
   }
+
   return results?.length > 0 ? formatResults(baseDir, results) : null
 }
 
 export async function runLintCheck(
   baseDir: string,
   lintDirs: string[],
-  lintDuringBuild: boolean = false
+  lintDuringBuild: boolean = false,
+  eslintOptions: any = null
 ): Promise<string | null> {
   try {
     // Find user's .eslintrc file
@@ -158,10 +159,23 @@ export async function runLintCheck(
     )
 
     // Write default ESLint config if none is present
-    await writeDefaultConfig(eslintrcFile, pkgJsonPath, packageJsonConfig)
+    // Check for /pages and src/pages is to make sure this happens in Next.js folder
+    if (
+      existsSync(path.join(baseDir, 'pages')) ||
+      existsSync(path.join(baseDir, 'src/pages'))
+    ) {
+      await writeDefaultConfig(eslintrcFile, pkgJsonPath, packageJsonConfig)
+    }
 
     // Run ESLint
-    return await lint(deps, baseDir, lintDirs, eslintrcFile, pkgJsonPath)
+    return await lint(
+      deps,
+      baseDir,
+      lintDirs,
+      eslintrcFile,
+      pkgJsonPath,
+      eslintOptions
+    )
   } catch (err) {
     throw err
   }

packages/next/lib/verifyAndLint.ts

@@ -2,6 +2,7 @@ import chalk from 'chalk'
 import { Worker } from 'jest-worker'
 import { existsSync } from 'fs'
 import { join } from 'path'
+import { ESLINT_DEFAULT_DIRS } from './constants'
 
 export async function verifyAndLint(
   dir: string,
@@ -20,7 +21,7 @@ export async function verifyAndLint(
     lintWorkers.getStdout().pipe(process.stdout)
     lintWorkers.getStderr().pipe(process.stderr)
 
-    const lintDirs = (configLintDirs ?? ['pages', 'components', 'lib']).reduce(
+    const lintDirs = (configLintDirs ?? ESLINT_DEFAULT_DIRS).reduce(
       (res: string[], d: string) => {
         const currDir = join(dir, d)
         if (!existsSync(currDir)) return res

test/integration/eslint/first-time-setup/.eslintrc

@@ -1,3 +1,4 @@
 {
+  "root": true,
   "extends": "next"
 }