ESLint configuration for Sage theme

.eslintrc.js

module.exports = {
  'root': true,
  'extends': [
    'eslint:recommended',
    'plugin:sonarjs/recommended',
    'plugin:unicorn/recommended',
    'es/2015/client',
  ],
  'globals': {
    'wp': true,
  },
  'env': {
    'node': true,
    'es6': true,
    'amd': true,
    'browser': true,
    'jquery': true,
  },
  'parserOptions': {
    'ecmaFeatures': {
      'globalReturn': true,
      'generators': true,
    },
    'ecmaVersion': 2018,
    'sourceType': 'module',
  },
  'plugins': [
    'import',
    'sonarjs',
    'unicorn',
  ],
  'settings': {
    'import/core-modules': [],
    'import/ignore': [
      'node_modules',
      '\\.(coffee|scss|css|less|hbs|svg|json)$',
    ],
  },
  'rules': {
    'quotes': ['error', 'single'],
    'comma-dangle': [
      'error',
      {
        'arrays': 'always-multiline',
        'objects': 'always-multiline',
        'imports': 'always-multiline',
        'exports': 'always-multiline',
        'functions': 'ignore',
      },
    ],
    'unicorn/filename-case': [
      'error',
      {
        'case': 'camelCase',
      },
    ],
    'linebreak-style': 0,
    'id-length': [ 2, {
      min: 2,
      max: Number.infinity,
      properties: 'always',
      exceptions: [ '_', 'i', 'j', 'x', 'y', 'z', '$' ]
    }],
    'sort-imports': [ 2, {
      ignoreCase: true,
      ignoreMemberSort: false,
      memberSyntaxSortOrder: [ 'none', 'single', 'multiple', 'all' ]
    }],
    'space-before-function-paren': ['error', {
      'anonymous': 'always',
      'named': 'never',
      'asyncArrow': 'always',
    }],
    'dot-location': ['error', 'property'],
  },
};

install-packages.sh

npm install --save-dev eslint@5.16.0  eslint-config-es eslint-plugin-sonarjs eslint-plugin-unicorn

First update eslint to the latest version and install the additional package.

When using with Sage, either fix the linting errors in the build scripts or exclude the build scripts from linting by updating in package.json: "lint:scripts": "eslint resources/assets/scripts".