Update ESLint to 9.x

eslint.config.mjs

@@ -0,0 +1,112 @@
+import ember from "eslint-plugin-ember";
+import globals from "globals";
+import babelParser from "@babel/eslint-parser";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import js from "@eslint/js";
+import { FlatCompat } from "@eslint/eslintrc";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+  recommendedConfig: js.configs.recommended,
+  allConfig: js.configs.all,
+});
+
+export default [
+  {
+    ignores: [
+      "blueprints/*/files/",
+      "declarations/",
+      "dist/",
+      "coverage/",
+      "!**/.*",
+      "**/.*/",
+      ".node_modules.ember-try/",
+    ],
+  },
+  ...compat.extends(
+    "eslint:recommended",
+    "plugin:ember/recommended",
+    "plugin:prettier/recommended",
+  ),
+  {
+    plugins: {
+      ember,
+    },
+
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+      },
+
+      parser: babelParser,
+      ecmaVersion: "latest",
+      sourceType: "module",
+
+      parserOptions: {
+        requireConfigFile: false,
+
+        babelOptions: {
+          plugins: [
+            [
+              "@babel/plugin-proposal-decorators",
+              {
+                decoratorsBeforeExport: true,
+              },
+            ],
+          ],
+        },
+      },
+    },
+
+    rules: {},
+  },
+  ...compat.extends("plugin:n/recommended").map((config) => ({
+    ...config,
+
+    files: [
+      "./.eslintrc.js",
+      "./.prettierrc.js",
+      "./.stylelintrc.js",
+      "./.template-lintrc.js",
+      "./ember-cli-build.js",
+      "./index.js",
+      "./testem.js",
+      "./blueprints/*/index.js",
+      "./config/**/*.js",
+      "./tests/dummy/config/**/*.js",
+    ],
+  })),
+  {
+    files: [
+      "./.eslintrc.js",
+      "./.prettierrc.js",
+      "./.stylelintrc.js",
+      "./.template-lintrc.js",
+      "./ember-cli-build.js",
+      "./index.js",
+      "./testem.js",
+      "./blueprints/*/index.js",
+      "./config/**/*.js",
+      "./tests/dummy/config/**/*.js",
+    ],
+
+    languageOptions: {
+      globals: {
+        ...Object.fromEntries(
+          Object.entries(globals.browser).map(([key]) => [key, "off"]),
+        ),
+        ...globals.node,
+      },
+
+      ecmaVersion: 5,
+      sourceType: "commonjs",
+    },
+  },
+  ...compat.extends("plugin:qunit/recommended").map((config) => ({
+    ...config,
+    files: ["tests/**/*-test.{js,ts}"],
+  })),
+];

package.json

@@ -84,7 +84,7 @@
     "ember-source-channel-url": "^3.0.0",
     "ember-template-lint": "^5.13.0",
     "ember-try": "^3.0.0",
-    "eslint": "^8.57.0",
+    "eslint": "^9.7.0",
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-ember": "^11.12.0",
     "eslint-plugin-n": "^16.6.2",
@@ -100,6 +100,9 @@
   },
   "peerDependencies": {
     "ember-source": ">= 4.0.0"
+  },
+    "resolutions": {
+      "globals": "^15.8.0"
   },
   "engines": {
     "node": ">= 18"