.eslintrc.js

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

module.exports = {
  root: true,
  env: {
    browser: true,
  },
  extends: ['airbnb-base', 'plugin:prettier/recommended'],
  plugins: ['prettier'],
  // add your custom rules here
  rules: {
    'class-methods-use-this': 'off',
    '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',
  },
};