.eslintrc.js

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

module.exports = {
  root: true,
  env: {
    browser: true,
  },
  extends: [
    'airbnb-base',
  ],
  // add your custom rules here
  rules: {
    'class-methods-use-this': 'off',
    'comma-dangle': ['error', {
      arrays: 'always-multiline',
      objects: 'always-multiline',
      imports: 'always-multiline',
      exports: 'always-multiline',
      functions: 'never',
    }],
    indent: ['error', 2, {
      SwitchCase: 1,
    }],
    'no-duplicate-imports': 'error',
    // risk only exist with semi-colon auto insertion. Not our case.
    'no-plusplus': 'off',
    'no-param-reassign': 'off',
    'no-underscore-dangle': ['error', {
      allowAfterSuper: true,
      allowAfterThis: true,
    }],
    'prefer-destructuring': 'off',
    // don't require .js extension when importing
    'import/extensions': ['error', 'always', { js: 'never' }],
    // allow optionalDependencies
    'import/no-extraneous-dependencies': ['error', {
      optionalDependencies: ['test/unit/index.js'],
    }],
    'import/prefer-default-export': 'off',
    // allow debugger during development
    'no-debugger': process.env.NODE_ENV === 'production' ? 'error' : 'off',
  },
};