Migrate ESLint config to Flat config

CHANGELOG.md

@@ -12,10 +12,11 @@
 
 ### Changed
 
+- Bump markdown-it to [v14.1.0](https://github.com/markdown-it/markdown-it/blob/master/CHANGELOG.md#1410---2024-03-19), and follow the latest spec of [CommonMark 0.31.2](https://spec.commonmark.org/0.31.2/) ([#393](https://github.com/marp-team/marpit/pull/393))
 - Switch package manager from yarn to npm ([#391](https://github.com/marp-team/marpit/pull/391))
 - Upgrade development Node.js to v20 LTS ([#392](https://github.com/marp-team/marpit/pull/392))
-- Bump markdown-it to [v14.1.0](https://github.com/markdown-it/markdown-it/blob/master/CHANGELOG.md#1410---2024-03-19), and follow the latest spec of [CommonMark 0.31.2](https://spec.commonmark.org/0.31.2/) ([#393](https://github.com/marp-team/marpit/pull/393))
 - Upgrade dependent packages to the latest version ([#393](https://github.com/marp-team/marpit/pull/393))
+- Migrate ESLint config to Flat config ([#394](https://github.com/marp-team/marpit/pull/394))
 
 ### Removed
 

eslint.config.mjs

@@ -0,0 +1,67 @@
+import babelParser from '@babel/eslint-parser'
+import js from '@eslint/js'
+import eslintConfigPrettier from 'eslint-config-prettier'
+import eslintPluginImportX from 'eslint-plugin-import-x'
+import globals from 'globals'
+
+export default [
+  js.configs.recommended,
+  // eslintPluginImportX.configs.recommended, // not yet available
+  eslintConfigPrettier,
+  {
+    languageOptions: {
+      parser: babelParser,
+      globals: {
+        ...globals.node,
+      },
+    },
+    linterOptions: {
+      reportUnusedDisableDirectives: 'error',
+    },
+    plugins: {
+      import: eslintPluginImportX,
+    },
+    rules: {
+      'import/order': [
+        'error',
+        {
+          alphabetize: {
+            order: 'asc',
+          },
+        },
+      ],
+      'max-len': [
+        'error',
+        {
+          code: 80,
+          tabWidth: 2,
+          ignoreUrls: true,
+          ignoreComments: false,
+          ignoreRegExpLiterals: true,
+          ignoreStrings: true,
+          ignoreTemplateLiterals: true,
+        },
+      ],
+    },
+  },
+  {
+    files: ['test/**/*', 'jest.*'],
+    languageOptions: {
+      globals: {
+        ...globals.jest,
+        context: 'readonly',
+      },
+    },
+  },
+  {
+    ignores: [
+      'coverage/**/*',
+      'dist/**/*',
+      'docs/**/*',
+      'jsdoc/**/*',
+      'lib/**/*',
+      'node_modules/**/*',
+      'plugin.js',
+    ],
+  },
+]

jest.setup.js

@@ -1,2 +1 @@
-/* eslint-env jest */
 global.context = describe

package.json

@@ -49,7 +49,7 @@
     "docs:style": "node ./docsify/build.js",
     "format": "prettier \"**/*.{css,html,js,json,md,scss,ts,yaml,yml}\"",
     "jsdoc": "rimraf jsdoc && jsdoc src -c .jsdoc.json",
-    "lint:js": "ESLINT_USE_FLAT_CONFIG=false eslint --report-unused-disable-directives .",
+    "lint:js": "eslint",
     "lint:css": "stylelint \"./**/*.{css,scss}\"",
     "prepack": "npm-run-all --parallel check:* lint:* test:coverage --sequential build",
     "preversion": "run-p check:* lint:* test:coverage",
@@ -73,6 +73,7 @@
     "eslint": "^9.2.0",
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-import-x": "^0.5.0",
+    "globals": "^15.2.0",
     "jest": "^29.7.0",
     "jest-junit": "^16.0.0",
     "jsdoc": "^4.0.3",

src/plugin.js

@@ -28,7 +28,6 @@
  * @returns {Function} Generated Marpit plugin.
  */
 function marpitPlugin(plugin) {
-  // eslint-disable-next-line func-names
   return function (md, ...args) {
     if (md.marpit) return plugin.call(this, md, ...args)
 

src/postcss/import/parse.js

@@ -1,4 +1,3 @@
-/* eslint consistent-return: 0 */
 /** @module */
 import postcssPlugin from '../../helpers/postcss_plugin'
 

test/plugin.js

@@ -1,7 +1,7 @@
 import markdownIt from 'markdown-it'
+import { Marpit } from '../src/index'
 import pluginAsDefaultExport from '../src/plugin'
 import { marpitPlugin } from '../src/plugin'
-import { Marpit } from '../src/index'
 
 describe('Plugin interface', () => {
   it('is compatible as CommonJS module', () => {