.eslintrc.js

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

module.exports = {
  root: true,
  parserOptions: {
    sourceType: 'module',
    parser: 'babel-eslint',
  },
  env: {
    browser: true,
    es6: true,
    node: true,
  },
  extends: ['plugin:vue/recommended', '@vue/airbnb'],
  // add your custom rules here
  rules: {
    // disallow reassignment of function parameters
    // disallow parameter object manipulation except for specific exclusions
    'no-param-reassign': [
      'error',
      {
        props: true,
        ignorePropertyModificationsFor: [
          'state', // for vuex state
          'acc', // for reduce accumulators
          'e', // for e.returnvalue
        ],
      },
    ],
    // don't require .vue extension when importing
    'import/extensions': [
      'error',
      'always',
      {
        js: 'never',
        vue: 'never',
      },
    ],
    'object-curly-newline': 'off',
    // allow optionalDependencies
    'import/no-extraneous-dependencies': [
      'error',
      {
        optionalDependencies: ['test/unit/index.js'],
      },
    ],
    'vue/html-closing-bracket-newline': [
      'error',
      {
        singleline: 'never',
        multiline: 'never',
      },
    ],
    // allow debugger during development
    'no-debugger': process.env.NODE_ENV === 'production' ? 2 : 0,
    'no-console': process.env.NODE_ENV === 'production' ? 2 : 0,
    // legacy from air-bnb-config v13 - would have to fix all otherwise
    'arrow-parens': [
      'error',
      'as-needed',
      {
        requireForBlockBody: true,
      },
    ],
  },
  overrides: [
    {
      files: ['**/__tests__/*.{j,t}s?(x)', '**/tests/unit/**/*.spec.{j,t}s?(x)'],
      env: {
        jest: true,
      },
    },
  ],
};