Add eslint config

files-override/js/eslint.config.mjs

@@ -0,0 +1,93 @@
+import globals from 'globals';
+import js from '@eslint/js';
+
+import ember from 'eslint-plugin-ember';
+import emberRecommended from 'eslint-plugin-ember/configs/recommended';
+import gjsRecommended from 'eslint-plugin-ember/configs/recommended-gjs';
+
+import prettier from 'eslint-plugin-prettier/recommended';
+import qunit from 'eslint-plugin-qunit';
+import n from 'eslint-plugin-n';
+
+import emberParser from 'ember-eslint-parser';
+import babelParser from '@babel/eslint-parser';
+
+const esmParserOptions = {
+  ecmaFeatures: { modules: true },
+  ecmaVersion: 'latest',
+  requireConfigFile: false,
+  babelOptions: {
+    plugins: [
+      ['@babel/plugin-proposal-decorators', { decoratorsBeforeExport: true }],
+    ],
+  },
+};
+
+export default [
+  js.configs.recommended,
+  prettier,
+  {
+    ignores: ['vendor/', 'dist/', 'node_modules/', 'coverage/', '!**/.*'],
+    linterOptions: {
+      reportUnusedDisableDirectives: 'error',
+    },
+  },
+  {
+    files: ['**/*.js'],
+    languageOptions: {
+      parser: babelParser,
+      parserOptions: esmParserOptions,
+      globals: {
+        ...globals.browser,
+      },
+    },
+    plugins: {
+      ember: ember,
+    },
+    rules: {
+      ...emberRecommended.rules,
+      ...gjsRecommended.rules,
+    },
+  },
+  {
+    files: ['**/*.gjs'],
+    languageOptions: {
+      parser: emberParser,
+      parserOptions: esmParserOptions,
+      globals: {
+        ...globals.browser,
+      },
+    },
+    plugins: {
+      ember: ember,
+    },
+    rules: {
+      ...emberRecommended.rules,
+      ...gjsRecommended.rules,
+    },
+  },
+  {
+    plugins: {
+      qunit,
+    },
+    files: ['tests/**/*-test.{js,gjs}'],
+  },
+  /**
+   * CJS node files
+   */
+  {
+    files: ['**/*.cjs', 'config/**/*.js'],
+    plugins: {
+      n,
+    },
+
+    languageOptions: {
+      globals: {
+        ...globals.node,
+      },
+
+      ecmaVersion: 6,
+      sourceType: 'script',
+    },
+  },
+];

index.js

@@ -3,7 +3,7 @@ const fs = require('fs');
 const { join } = require('path');
 const emberCliUpdate = require('./lib/ember-cli-update');
 const copyWithTemplate = require('./lib/copy-with-template');
-const { rm } = require('fs/promises');
+const { rm, readFile } = require('fs/promises');
 
 const appBlueprint = Blueprint.lookup('app');
 
@@ -36,8 +36,39 @@ module.exports = {
   },
 
   async updateDeps(options) {
+    let manifestPath = join(options.target, 'package.json');
+    let manifestBuffer = await readFile(manifestPath);
+    let manifest = JSON.parse(manifestBuffer.toString());
+
+    let existingDeps = [
+      ...Object.keys(manifest.dependencies || {}),
+      ...Object.keys(manifest.devDependencies || {}),
+    ];
+
+    let ensureLatestDeps = ['eslint', 'eslint-plugin-ember', 'eslint-plugin-n'];
+
     // this.addPackagesToProject doesn't respect the packageManager that the blueprint specified 🙈 so we're skipping a level here
     let installTask = this.taskFor('npm-install');
+    let uninstallTask = this.taskFor('npm-uninstall');
+
+    await uninstallTask.run({
+      'save-dev': true,
+      verbose: false,
+      packages: [
+        // Not needed anymore
+        'ember-fetch',
+        'broccoli-asset-rev',
+        'ember-cli-app-version',
+        'ember-cli-clean-css',
+        'ember-cli-dependency-checker',
+        'ember-cli-sri',
+        'ember-cli-terser',
+
+        ...ensureLatestDeps,
+      ].filter((depToRemove) => existingDeps.includes(depToRemove)),
+      packageManager: options.packageManager,
+    });
+
     await installTask.run({
       'save-dev': true,
       verbose: false,
@@ -50,37 +81,21 @@ module.exports = {
         'vite',
         '@rollup/plugin-babel',
         'decorator-transforms',
+
+        ...ensureLatestDeps,
+        // Needed for eslint
+        'globals',
       ],
       packageManager: options.packageManager,
     });
-
-    let uninstallTask = this.taskFor('npm-uninstall');
-    const packages = [
-      'ember-fetch',
-      'broccoli-asset-rev',
-      'ember-cli-app-version',
-      'ember-cli-clean-css',
-      'ember-cli-dependency-checker',
-      'ember-cli-sri',
-      'ember-cli-terser',
-    ];
-
-    for (const package of packages) {
-      try {
-        await uninstallTask.run({
-          'save-dev': true,
-          verbose: false,
-          packages: [package],
-          packageManager: options.packageManager,
-        });
-      } catch {
-        console.log(`Could not uninstall ${package}`);
-      }
-    }
   },
 
   async afterInstall(options) {
-    const filesToDelete = ['app/index.html'];
+    const filesToDelete = [
+      'app/index.html',
+      // replaced with the new ESLint flat config
+      '.eslintrc.js',
+    ];
 
     for (let file of filesToDelete) {
       await rm(join(options.target, file));