neutrino-dev/packages/neutrino-middleware-eslint/index.js

const merge = require('deepmerge');
const clone = require('lodash.clonedeep');
const { join } = require('path');

const IF_NOT_DEV = process.env.NODE_ENV !== 'development';
const MODULES = join(__dirname, 'node_modules');

module.exports = options => (config, neutrino) => {
  config.resolve.modules.add(MODULES);
  config.resolveLoader.modules.add(MODULES);
  config.module
    .rule('lint')
    .test(options.test || /\.(js|jsx)$/)
    .pre()
    .include(options.include)
    .loader('eslint', require.resolve('eslint-loader'), merge({
      failOnError: IF_NOT_DEV,
      emitWarning: IF_NOT_DEV,
      emitError: IF_NOT_DEV,
      cwd: process.cwd(),
      useEslintrc: false,
      root: true,
      plugins: ['babel'],
      baseConfig: {},
      envs: ['es6'],
      parser: 'babel-eslint',
      parserOptions: {
        ecmaVersion: 2017,
        sourceType: 'module',
        ecmaFeatures: {
          objectLiteralDuplicateProperties: false,
          generators: true,
          impliedStrict: true
        }
      },
      settings: {},
      globals: ['process'],
      rules: {}
    }, options.eslint || {}));

  neutrino.eslintrc = () => {
    const options = clone(config.module.rule('lint').loaders.get('eslint').options);

    options.extends = options.baseConfig.extends;
    options.useEslintrc = true;
    options.env = options.envs.reduce((env, key) => Object.assign(env, { [key]: true }), {});
    options.globals = options.globals.reduce((globals, key) => Object.assign(globals, { [key]: true }), {});
    ['envs', 'baseConfig', 'failOnError', 'emitWarning', 'emitError'].map(method => delete options[method]);

    return options;
  };
};