.eslintrc.js

// https://eslint.org/docs/user-guide/configuring

module.exports = {
  root: true,
  parserOptions: {
    parser: 'babel-eslint',
    sourceType: 'module'
  },
  env: {
    browser: true,
  },
  extends: ['airbnb-base', 'plugin:vue/recommended'],
  // check if imports actually resolve
  'settings': {
    'import/resolver': {
      'webpack': {
        'config': 'build/webpack.base.conf.js'
      }
    }
  },
  // add your custom rules here
  'rules': {
    // don't require .vue extension when importing
    'import/extensions': ['error', 'always', {
      'js': 'never',
      'vue': 'never'
    }],
    // allow optionalDependencies
    'import/no-extraneous-dependencies': ['error', {
      'optionalDependencies': ['test/unit/index.js']
    }],
    // allow debugger during development
    'no-debugger': process.env.NODE_ENV === 'production' ? 2 : 0,
    'no-confusing-arrow': 'off',
    // allow i++ in for loop
    'no-plusplus': ['error', {
      'allowForLoopAfterthoughts': true
    }],

    // VUE

    'vue/max-attributes-per-line': [2, {
      'singleline': 3,
      'multiline': {
        'max': 1,
        'allowFirstLine': false
      }
    }],
    'no-param-reassign': [
      'error',
      {
        'props': true,
        'ignorePropertyModificationsFor': [
          'state',
          'acc',
          'e',
          'error',
          'ctx',
          'req',
          'request',
          'res',
          'response',
          'result',
        ]
      }
    ],
  }
}