.eslintrc.js

module.exports = {
  root: true,
  parserOptions: {
    ecmaVersion: 2017,
    sourceType: 'module',
  },
  plugins: ['prettier', 'ember'],
  extends: ['eslint:recommended', 'plugin:ember/recommended', 'prettier'],
  env: {
    browser: true,
  },
  rules: {
    'comma-dangle': [
      'error',
      {
        arrays: 'always-multiline',
        objects: 'always-multiline',
        imports: 'always-multiline',
        exports: 'always-multiline',
        functions: 'never',
      },
    ],
    'prettier/prettier': ['error', { trailingComma: 'es5', singleQuote: true }],
  },
  overrides: [
    // node files
    {
      files: [
        '.eslintrc.js',
        '.template-lintrc.js',
        'ember-cli-build.js',
        'index.js',
        'testem.js',
        'blueprints/*/index.js',
        'config/**/*.js',
        'tests/dummy/config/**/*.js',
      ],
      excludedFiles: [
        'addon/**',
        'addon-test-support/**',
        'app/**',
        'tests/dummy/app/**',
      ],
      parserOptions: {
        sourceType: 'script',
        ecmaVersion: 2015,
      },
      env: {
        browser: false,
        node: true,
      },
      plugins: ['node'],
      rules: Object.assign(
        {},
        require('eslint-plugin-node').configs.recommended.rules,
        {
          // add your custom rules and overrides for node files here
        }
      ),
    },
  ],
};