.eslintrc.js

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

module.exports = {
  root: true,
  parserOptions: {
    parser: 'babel-eslint',
    ecmaVersion: 2017,
    sourceType: 'module'
  },
  plugins: ['html', 'vue'],
  extends: [
    'eslint:recommended',
    'plugin:vue/recommended',
    'plugin:import/errors',
    'plugin:import/warnings'
  ],
  env: {
    browser: true,
    node: true,
    commonjs: true,
    es6: true,
    jest: true
  },
  rules: {
    // allow async-await
    'generator-star-spacing': 'off',
     // don't require .vue extension when importing
    'import/extensions': ['error', 'always', {
      'js': 'never',
      'vue': 'never'
    }],
    // 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
      ]
    }],
    // allow optionalDependencies
    'import/no-extraneous-dependencies': ['error', {
      optionalDependencies: ['test/index.js']
    }],
    // allow debugger during development
    'no-debugger': process.env.NODE_ENV === 'production' ? 'error' : 'off'
  },
  "settings": {
    // resolve using plugin babel module resolver
    "import/resolver": {
      "babel-module": {}
    }
  }
}