Update own config to new flat ESLint (#11)

* Upgrade dependencies

* Upgrade to ESLint v9 (alpha)

* Upgrade own ESLint config to new flat config

Also added package "globals"

* Update folders that ESLint should ignore

* Fix ESLint code violations

* Add global ignore pattern to docs

* Only test with newer versions of node

* Only test on latest node version

Otherwise, v9 of ESLint can't be installed

* Run npm with `--legacy-peer-deps` flag

This is because we are using an alpha version of ESLint.

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        node: [16, 17, 18, 19, 20, 21]
+        node: [18, 19, 20, 21]
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
@@ -22,7 +22,7 @@ jobs:
         with:
           node-version: ${{ matrix.node }}
       - name: Install dependencies
-        run: npm install
+        run: npm install --legacy-peer-deps
         env:
           CI: true
       - name: Run Mocha tests

.mocharc.js

@@ -1,6 +1,6 @@
 module.exports = {
-    "spec": "tests/**/*.js",
-    "ignore": [
-        "tests/fixtures/**"
-    ],
-}
+  spec: "tests/**/*.js",
+  ignore: [
+    "tests/fixtures/**",
+  ],
+};

.vscode/settings.json

@@ -1,5 +1,6 @@
 {
     "eslint.format.enable": true,
+    "eslint.experimental.useFlatConfig": true,
     "[javascript]": {
         "editor.formatOnSave": false, // to avoid formatting twice (ESLint + VSCode)
         "editor.defaultFormatter": "dbaeumer.vscode-eslint"
@@ -8,5 +9,5 @@
         "source.fixAll.eslint": "explicit"
     },
     // this disables VSCode built-int formatter (instead we want to use ESLint)
-    "javascript.validate.enable": false
+    "javascript.validate.enable": false,
 }

README.md

@@ -62,13 +62,23 @@ const customGlobals = {
   MyGlobalVariableOrFunctionOrClassOrWhatever: "readable",
 };
 
+// [1] https://eslint.org/docs/latest/use/configure/configuration-files-new#globally-ignoring-files-with-ignores
+
 export default [
   js.configs.recommended,
   erb.configs.recommended,
+  // Globally ignoring the following files
+  // "Note that only global ignores patterns can match directories.
+  // 'ignores' patterns that are specific to a configuration will
+  // only match file names." ~ see [1]
   {
     ignores: [
       "node_modules/",
+      "tests/fixtures/",
+      "tmp/",
     ],
+  },
+  {
     plugins: {
       "@stylistic": stylistic,
     },

eslint.config.js

@@ -0,0 +1,40 @@
+const js = require("@eslint/js");
+const stylistic = require("@stylistic/eslint-plugin");
+const globals = require("globals");
+
+const customizedStylistic = stylistic.configs.customize({
+  "indent": 2,
+  "jsx": false,
+  "quote-props": "always",
+  "semi": "always",
+  "brace-style": "1tbs",
+});
+
+module.exports = [
+  js.configs.recommended,
+  {
+    ignores: [
+      "node_modules/",
+      "tests/fixtures/",
+      "tmp/",
+    ],
+  },
+  {
+    plugins: {
+      "@stylistic": stylistic,
+    },
+    rules: {
+      ...customizedStylistic.rules,
+      "no-unused-vars": ["warn", { argsIgnorePattern: "^_" }],
+      "@stylistic/quotes": ["error", "double", { avoidEscape: true }],
+    },
+    languageOptions: {
+      ecmaVersion: 2024,
+      sourceType: "module",
+      globals: {
+        ...globals.node,
+        ...globals.mocha,
+      },
+    },
+  },
+];

lib/postprocess.js

@@ -1,5 +1,5 @@
 const cache = require("./cache.js");
-const { coordinatesToIndex, indexToColumn } = require("./file_coordinates.js");
+const { coordinatesToIndex } = require("./file_coordinates.js");
 const { calculateOffset } = require("./offset_calculation.js");
 const { transformFix } = require("./autofix.js");
 

package.json

@@ -33,13 +33,16 @@
   "devDependencies": {
     "@stylistic/eslint-plugin": "^1.3.3",
     "chai": "^4.3.10",
-    "eslint": "^8.54.0",
+    "eslint": "^9.0.0-alpha.0",
+    "globals": "^13.24.0",
     "mocha": "^10.2.0"
   },
   "scripts": {
+    "lint": "eslint .",
+    "lint-fix": "eslint --fix .",
     "test": "mocha",
     "whats-included": "npm pack --dry-run",
     "bump-version": "npm run test && npm version --no-git-tag-version",
     "publish-final": "npm run test && npm publish"
   }
-}
+}

tests/postprocess.js

@@ -7,7 +7,7 @@ const cache = require("../lib/cache.js");
 
 describe("postprocess", () => {
   it("deletes file from cache after postprocessing", () => {
-    const text = `console.log("Hello world!");`;
+    const text = 'console.log("Hello world!");';
     const name = "testfile.js";
 
     pre(text, name);