.eslintrc.js

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

module.exports = {
  root: true,
  parserOptions: {
    parser: 'babel-eslint',
    sourceType: 'module'
  },
  env: {
    browser: true,
    jest: true
  },
  extends: ['airbnb-base','plugin:vue/essential'],
  // required to lint *.vue files
  plugins: ['vue'],
  // 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'
    }],
    'max-len': ['error', 
      { 'code': 200 }
    ],
    // allow optionalDependencies
    'import/no-extraneous-dependencies': ['error', {
      optionalDependencies: ['test/unit/index.js']
    }],
    'no-unused-expressions': ['error', { allowTernary: true }],
    // allow debugger during development
    'no-debugger': process.env.NODE_ENV === 'production' ? 'error' : 'off',
    'vue/order-in-components': ['error', {
      'order': [
        'el',
        'name',
        'parent',
        'functional',
        ['delimiters', 'comments'],
        ['components', 'directives', 'filters'],
        'extends',
        'mixins',
        'inheritAttrs',
        'model',
        ['props', 'propsData'],
        'data',
        'computed',
        'watch',
        'LIFECYCLE_HOOKS',
        'methods',
        ['template', 'render'],
        'renderError'
      ]
    }]
  }
}