Rewrite .eslintrc.tests_newsletter_editor.js to new config format

[MAILPOET-5015]

mailpoet/eslint.config.js

@@ -1,6 +1,7 @@
 const es5Config = require('@mailpoet/eslint-config/eslint-es5.config');
 const es6Config = require('@mailpoet/eslint-config/eslint-es6.config');
 const esTsConfig = require('@mailpoet/eslint-config/eslint-ts.config');
+const esTestsNewsletterEditorConfig = require('@mailpoet/eslint-config/eslint-tests-newsletter-editor.config');
 
 module.exports = [
   {
@@ -18,4 +19,9 @@ module.exports = [
     ...config,
     files: ['assets/js/src/**/*.{ts,tsx}'],
   })),
+  ...esTestsNewsletterEditorConfig.map((config) => ({
+    ...config,
+    files: ['tests/javascript_newsletter_editor/**/*.js'],
+    ignores: ['tests/javascript_newsletter_editor/testBundles/**'],
+  })),
 ];

mailpoet/package.json

@@ -4,8 +4,7 @@
     "extends @wordpress/browserslist-config"
   ],
   "scripts": {
-    "lint": "eslint --max-warnings 0 'assets/js/src/**' && pnpm run lint-tests",
-    "lint-tests": "ESLINT_USE_FLAT_CONFIG=false eslint -c ../packages/js/eslint-config/.eslintrc.tests_newsletter_editor.js --max-warnings 0 'tests/javascript_newsletter_editor'",
+    "lint": "eslint --max-warnings 0 'assets/js/src/**' 'tests/javascript_newsletter_editor/**'",
     "autoprefixer": "postcss assets/dist/css/*.css --use autoprefixer --no-map --replace",
     "scss": "sass assets/css/src/:assets/dist/css/ --style compressed",
     "stylelint": "stylelint --fix",
@@ -19,8 +18,7 @@
   },
   "lint-staged": {
     "*.{scss,css}": "pnpm run stylelint",
-    "!(*spec).{js,jsx,ts,tsx}": "eslint --max-warnings 0",
-    "**/newsletter_editor/**/*spec.js": "ESLINT_USE_FLAT_CONFIG=false eslint -c ../packages/js/eslint-config/.eslintrc.tests_newsletter_editor.js --max-warnings 0",
+    "*.{js,jsx,ts,tsx}": "eslint --max-warnings 0",
     "*.php": [
       "phplint",
       "./do qa:code-sniffer",

packages/js/eslint-config/.eslintrc.tests_newsletter_editor.js

@@ -1,20 +0,0 @@
-module.exports = {
-  extends: ['airbnb/legacy', 'prettier'],
-  env: {
-    amd: true,
-    mocha: true,
-  },
-  parser: '@babel/eslint-parser',
-  parserOptions: {
-    ecmaVersion: 6,
-    sourceType: 'module',
-  },
-  rules: {
-    'no-only-tests/no-only-tests': 2,
-    // Exceptions
-    'func-names': 0,
-    // Temporary
-    'no-underscore-dangle': 0,
-  },
-  plugins: ['no-only-tests'],
-};

packages/js/eslint-config/eslint-tests-newsletter-editor.config.js

@@ -0,0 +1,40 @@
+const babelParser = require('@babel/eslint-parser');
+const FlatCompat = require('@eslint/eslintrc').FlatCompat;
+const airbnbLegacyConfig = require('eslint-config-airbnb/legacy');
+const prettierConfig = require('eslint-config-prettier');
+const importPlugin = require('eslint-plugin-import');
+const noOnlyTestsPlugin = require('eslint-plugin-no-only-tests');
+const globals = require('globals');
+
+// compat configs
+const compat = new FlatCompat({ baseDirectory: __dirname });
+const airbnbLegacyCompatConfig = compat.config(airbnbLegacyConfig);
+const prettierCompatConfig = compat.config(prettierConfig);
+
+module.exports = [
+  ...airbnbLegacyCompatConfig,
+  ...prettierCompatConfig,
+  {
+    languageOptions: {
+      parser: babelParser,
+      parserOptions: {
+        ecmaVersion: 6,
+        sourceType: 'module',
+      },
+      globals: {
+        ...globals.mocha,
+      },
+    },
+    plugins: {
+      import: importPlugin,
+      'no-only-tests': noOnlyTestsPlugin,
+    },
+    rules: {
+      'no-only-tests/no-only-tests': 2,
+      // Exceptions
+      'func-names': 0,
+      // Temporary
+      'no-underscore-dangle': 0,
+    },
+  },
+];