Update ESLint Config to Support ESLint 9+

lib/generators/rolemodel/linters/eslint/eslint_generator.rb

@@ -20,7 +20,7 @@ def install_eslint
       end
 
       def add_config
-        template '.eslintrc.cjs', '.eslintrc.cjs'
+        template 'eslint.config.js', 'eslint.config.js'
       end
 
       def add_eslint_command_to_package_json

lib/generators/rolemodel/linters/eslint/templates/eslint.config.js

@@ -0,0 +1,92 @@
+import globals from 'globals'
+
+export default [
+  {
+    ignores: ['app/assets/builds/**/*']
+  },
+  { name: 'airbnb' },
+  {
+    languageOptions: {
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true
+        },
+        ecmaVersion: 'latest',
+        globals: {
+          ...globals.browser,
+          ...globals.es6
+        }
+      }
+    },
+    rules: {
+      'no-unused-vars': [
+        'error',
+        {
+          argsIgnorePattern: '^_', // Allow unused arguments starting with an underscore
+          varsIgnorePattern: '^_' // Allow unused variables starting with an underscore
+        }
+      ],
+
+      // No semicolons
+      semi: ['error', 'never'],
+      'no-unexpected-multiline': 'error',
+
+      // 1. We follow the convention of naming "private" properties with a leading underscore
+      // 2. This conflicts with the no-unused-vars config
+      'no-underscore-dangle': 'off',
+
+      // Multiple variable declarations (without assignment) on the same line
+      // without multiple let/const
+      'one-var': ['error', { initialized: 'never', uninitialized: 'always' }],
+      'one-var-declaration-per-line': ['error', 'initializations'],
+
+      // Don't require naming all non-arrow functions. Modern browsers can usually
+      // detect the correct name if it's assigned to a variable or property.
+      'func-names': 'off',
+
+      // Don't require instance methods to use `this` (the rule name is confusing)
+      'class-methods-use-this': 'off',
+
+      // Turning this on addresses some quirks with using `var`. It's unnecessary
+      // for `let` and `const`.
+      'no-loop-func': 'off',
+
+      // Turning this on requires destructuring in too many cases
+      'prefer-destructuring': 'off',
+
+      // Turning this on prevents directly importing sub-dependencies
+      'import/no-extraneous-dependencies': 'off',
+
+      // One-liner methods can be readable without the extra spacing
+      'lines-between-class-members': ['error', 'always', { exceptAfterSingleLine: true }],
+
+      // Allow assigning to properties of arguments (might consider completely disabling this rule)
+      'no-param-reassign': ['error', { props: false }],
+
+      // Sufficiently high that it won't be too annoying
+      'max-len': ['warn', 130],
+
+      // Disabled because it complains if you mix `return` with `return <value>` in a function
+      'consistent-return': 'off',
+
+      // Allow patterns like `while ((a = getNextValue()))`
+      'no-cond-assign': ['error', 'except-parens'],
+
+      // 'import/extensions': ['warn', 'ignorePackages'],
+
+      // Default disallows mixing exponentiation with other arithmetic operators
+      'no-mixed-operators': [
+        'error',
+        {
+          allowSamePrecedence: false, // Could also make this true
+          groups: [
+            ['&', '|', '^', '~', '<<', '>>', '>>>'],
+            ['==', '!=', '===', '!==', '>', '>=', '<', '<='],
+            ['&&', '||'],
+            ['in', 'instanceof']
+          ]
+        }
+      ]
+    }
+  }
+]