.eslintrc.js

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

module.exports = {
  root: true,
  parserOptions: {
    parser: 'babel-eslint',
  },
  env: {
    browser: true,
  },
  extends: [
    'plugin:vue/essential',
    'plugin:vue/recommended',
    'plugin:vue/strongly-recommended',
    'airbnb-base'
  ],
  // 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: {
    indent: ['error', 2],
    semi: ["error", "never"],
    'vue/html-indent': ['error', 2],
    // 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/unit/index.js'],
    }],
    // allow debugger during development
    'no-debugger': process.env.NODE_ENV === 'production' ? 'error' : 'off',
  },
};