<%= add_documentation_reference(config, “// github.com/shakacode/react_on_rails_demo_ssr_hmr/blob/master/config/webpack/serverWebpackConfig.js”) %>

const { merge, config } = require(‘shakapacker’); const commonWebpackConfig = require(‘./commonWebpackConfig’);

const webpack = require(‘webpack’);

const configureServer = () => {

// We need to use "merge" because the clientConfigObject, EVEN after running
// toWebpackConfig() is a mutable GLOBAL. Thus any changes, like modifying the
// entry value will result in changing the client config!
// Using webpack-merge into an empty object avoids this issue.
const serverWebpackConfig = commonWebpackConfig();

// We just want the single server bundle entry
const serverEntry = {
  'server-bundle': serverWebpackConfig.entry['server-bundle'],
};

if (!serverEntry['server-bundle']) {
  throw new Error(
    "Create a pack with the file name 'server-bundle.js' containing all the server rendering files",
  );
}

serverWebpackConfig.entry = serverEntry;

// Remove the mini-css-extract-plugin from the style loaders because
// the client build will handle exporting CSS.
// replace file-loader with null-loader
serverWebpackConfig.module.rules.forEach((loader) => {
  if (loader.use && loader.use.filter) {
    loader.use = loader.use.filter(
      (item) => !(typeof item === 'string' && item.match(/mini-css-extract-plugin/)),
    );
  }
});

// No splitting of chunks for a server bundle
serverWebpackConfig.optimization = {
  minimize: false,
};
serverWebpackConfig.plugins.unshift(new webpack.optimize.LimitChunkCountPlugin({ maxChunks: 1 }));

// Custom output for the server-bundle that matches the config in
// config/initializers/react_on_rails.rb
serverWebpackConfig.output = {
  filename: 'server-bundle.js',
  globalObject: 'this',
  // If using the React on Rails Pro node server renderer, uncomment the next line
  // libraryTarget: 'commonjs2',
  path: config.outputPath,
  publicPath: config.publicPath,
  // https://webpack.js.org/configuration/output/#outputglobalobject
};

// Don't hash the server bundle b/c would conflict with the client manifest
// And no need for the MiniCssExtractPlugin
serverWebpackConfig.plugins = serverWebpackConfig.plugins.filter(
  (plugin) =>
    plugin.constructor.name !== 'WebpackAssetsManifest' &&
    plugin.constructor.name !== 'MiniCssExtractPlugin' &&
    plugin.constructor.name !== 'ForkTsCheckerWebpackPlugin',
);

// Configure loader rules for SSR
// Remove the mini-css-extract-plugin from the style loaders because
// the client build will handle exporting CSS.
// replace file-loader with null-loader
const rules = serverWebpackConfig.module.rules;
rules.forEach((rule) => {
  if (Array.isArray(rule.use)) {
    // remove the mini-css-extract-plugin and style-loader
    rule.use = rule.use.filter((item) => {
      let testValue;
      if (typeof item === 'string') {
        testValue = item;
      } else if (typeof item.loader === 'string') {
        testValue = item.loader;
      }
      return !(testValue.match(/mini-css-extract-plugin/) || testValue === 'style-loader');
    });
    const cssLoader = rule.use.find((item) => {
      let testValue;

      if (typeof item === 'string') {
        testValue = item;
      } else if (typeof item.loader === 'string') {
        testValue = item.loader;
      }

      return testValue.includes('css-loader');
    });
    if (cssLoader && cssLoader.options) {
      cssLoader.options.modules = { exportOnlyLocals: true };
    }

    // Skip writing image files during SSR by setting emitFile to false
  } else if (rule.use && (rule.use.loader === 'url-loader' || rule.use.loader === 'file-loader')) {
    rule.use.options.emitFile = false;
  }
});

// eval works well for the SSR bundle because it's the fastest and shows
// lines in the server bundle which is good for debugging SSR
// The default of cheap-module-source-map is slow and provides poor info.
serverWebpackConfig.devtool = 'eval';

// If using the default 'web', then libraries like Emotion and loadable-components
// break with SSR. The fix is to use a node renderer and change the target.
// If using the React on Rails Pro node server renderer, uncomment the next line
// serverWebpackConfig.target = 'node'

return serverWebpackConfig;

};

module.exports = configureServer;