.eslintrc.js

module.exports = {
  env: {
    browser: false,
    es2021: true,
    node: true,
    mocha: true,
    jest: true
  },
  extends: [
    'eslint:recommended'
  ],
  parserOptions: {
    ecmaVersion: 'latest',
    sourceType: 'module'
  },
  rules: {
    // Error prevention
    'no-console': 'off', // Allow console for CLI tool
    'no-unused-vars': ['error', { 
      argsIgnorePattern: '^_',
      varsIgnorePattern: '^_' 
    }],
    'no-undef': 'error',
    'no-unreachable': 'error',
    'no-duplicate-imports': 'error',
    
    // Code quality
    'prefer-const': 'error',
    'no-var': 'error',
    'object-shorthand': 'error',
    'prefer-arrow-callback': 'error',
    'prefer-template': 'error',
    
    // Style consistency
    'indent': ['error', 2],
    'quotes': ['error', 'single', { avoidEscape: true }],
    'semi': ['error', 'always'],
    'comma-dangle': ['error', 'never'],
    'eol-last': ['error', 'always'],
    'no-trailing-spaces': 'error',
    
    // Best practices
    'eqeqeq': ['error', 'always'],
    'curly': ['error', 'all'],
    'no-eval': 'error',
    'no-implied-eval': 'error',
    'no-new-func': 'error',
    'no-script-url': 'error',
    
    // Security
    'no-unsafe-finally': 'error',
    'no-unsafe-negation': 'error'
  },
  overrides: [
    {
      files: ['test/**/*.js', '**/*.test.js', '**/*.spec.js'],
      env: {
        mocha: true,
        jest: true
      },
      rules: {
        'no-unused-expressions': 'off' // For chai assertions
      }
    }
  ]
};