index.js

const react = require('@neutrinojs/react');
const banner = require('@neutrinojs/banner');
const merge = require('deepmerge');
const nodeExternals = require('webpack-node-externals');
const { extname, join, basename } = require('path');
const { readdirSync } = require('fs');

module.exports =
  (opts = {}) =>
  (neutrino) => {
    const options = merge(
      {
        html: process.env.NODE_ENV === 'development' && {
          title: 'React Preview',
        },
        externals: opts.externals !== false && {},
        style: {
          extract: {
            plugin: {
              // Override the @neutrinojs/react production behaviour of hashed CSS
              // filenames, and output to the build root, not an `assets/` subdirectory.
              filename: '[name].css',
            },
          },
        },
        devtool: {
          production: 'source-map',
        },
        targets: { browsers: 'ie 9' },
      },
      opts,
    );

    neutrino.config.when(
      process.env.NODE_ENV === 'development',
      () => {
        neutrino.use(react(options));
      },
      () => {
        const components = join(
          neutrino.options.source,
          options.components || 'components',
        );

        Object.keys(neutrino.options.mains).forEach((key) => {
          delete neutrino.options.mains[key]; // eslint-disable-line no-param-reassign
        });

        readdirSync(components).forEach((component) => {
          // eslint-disable-next-line no-param-reassign
          neutrino.options.mains[basename(component, extname(component))] = {
            entry: join(components, component),
          };
        });

        const pkg = neutrino.options.packageJson || {};
        const hasSourceMap =
          (pkg.dependencies && 'source-map-support' in pkg.dependencies) ||
          (pkg.devDependencies && 'source-map-support' in pkg.devDependencies);

        neutrino.use(react(options));

        neutrino.config
          .when(options.externals, (config) =>
            config.externals([nodeExternals(options.externals)]),
          )
          .when(hasSourceMap, () => neutrino.use(banner()))
          // Disable the chunking behaviour inherited from the react preset
          .optimization.splitChunks(false)
          .runtimeChunk(false)
          .end()
          .output // Override hashed filename/subdirectory usage inherited from @neutrinojs/react.
          .filename('[name].js')
          .library('[name]')
          .libraryTarget('umd')
          .umdNamedDefine(true);
      },
    );
  };