build-server.js

'use strict';

// Do this as the first thing so that any code reading it knows the right env.
process.env.BABEL_ENV = 'production';
process.env.NODE_ENV = 'production';

// Makes the script crash on unhandled rejections instead of silently
// ignoring them. In the future, promise rejections that are not handled will
// terminate the Node.js process with a non-zero exit code.
process.on('unhandledRejection', err => {
  throw err;
});

const path = require('path');
const fs = require('fs-extra');
const chalk = require('chalk');
// use the webpack from react-scripts to prevent version inconsistence
const webpack = require('webpack');
const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles');
const formatWebpackMessages = require('react-dev-utils/formatWebpackMessages');
const printHostingInstructions = require('react-dev-utils/printHostingInstructions');
const FileSizeReporter = require('react-dev-utils/FileSizeReporter');
const printBuildError = require('react-dev-utils/printBuildError');

const measureFileSizesBeforeBuild =
FileSizeReporter.measureFileSizesBeforeBuild;
const printFileSizesAfterBuild = FileSizeReporter.printFileSizesAfterBuild;

// These sizes are pretty large. We'll warn for bundles exceeding them.
const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024;
const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024;

const crs = require('create-react-scripts');

const serverlize = require('../config/webpack.config.server');
// rewire the result to integrate with other plugins
const rewireResult = crs.rewire();
// obtain the paths
const paths = rewireResult.paths;
// obtain the webpack config
const config = rewireResult.webpack;

// Warn and crash if required files are missing
if (!checkRequiredFiles([paths.appIndexJs, paths.appServerJs])) {
  process.exit(1);
}

// we can run the server-side build
function buildServer() {
  console.log();
  console.log(`${chalk.cyan('SERVER-SIDE')}`);
  console.log('===========================================================');
  fs.emptyDirSync(paths.appServerBuild);
  console.log('Creating a server-side production build...');

  let compiler = webpack(serverlize(paths, config));
  return new Promise((resolve, reject) => {
    compiler.run((err, stats) => {
      if (err) {
        return reject(err);
      } 
      const messages = formatWebpackMessages(stats.toJson({}, true));
      if (messages.errors.length) {
        // Only keep the first error. Others are often indicative
        // of the same problem, but confuse the reader with noise.
        if (messages.errors.length > 1) {
          messages.errors.length = 1;
        }
        return reject(new Error(messages.errors.join('\n\n')));
      }
      if (
        process.env.CI &&
        (typeof process.env.CI !== 'string' ||
          process.env.CI.toLowerCase() !== 'false') &&
        messages.warnings.length
      ) {
        console.log(
          chalk.yellow(
            '\nTreating warnings as errors because process.env.CI = true.\n' +
              'Most CI servers set it automatically.\n'
          )
        );
        return reject(new Error(messages.warnings.join('\n\n')));
      }
      return resolve({
        stats,
        warnings: messages.warnings,
      });
    });
  }).then(
    ({ stats, warnings }) => {
      if (warnings.length) {
        console.log(chalk.yellow('Compiled with warnings.\n'));
        console.log(warnings.join('\n\n'));
        console.log(
          '\nSearch for the ' +
            chalk.underline(chalk.yellow('keywords')) +
            ' to learn more about each warning.'
        );
        console.log(
          'To ignore, add ' +
            chalk.cyan('// eslint-disable-next-line') +
            ' to the line before.\n'
        );
      } else {
        console.log(chalk.green('Compiled successfully.\n'));
      }
      console.log(`The ${chalk.cyan(path.relative(process.cwd(), paths.appServerBuild))} folder is ready.`);
      console.log(`You may run it in ${chalk.cyan('node')} environment`);
      console.log();
      console.log(`  ${chalk.cyan('node')} ${chalk.cyan(path.relative(process.cwd(), paths.appServerBuild))}`);
      console.log();
    },
    err => {
      console.log(chalk.red('Failed to compile.\n'));
      printBuildError(err);
      process.exit(1);
    }
  );
}

console.log();
console.log(`${chalk.cyan('CLIENT-SIDE')}`);
console.log('===========================================================');
// First, read the current file sizes in build directory.
// This lets us display how much they changed later.
measureFileSizesBeforeBuild(paths.appBuild)
.then(previousFileSizes => {
  // Remove all content but keep the directory so that
  // if you're in it, you don't end up in Trash
  fs.removeSync(path.join(paths.appAssets, 'assets.json'));
  fs.emptyDirSync(paths.appBuild);
  // Merge with the public folder
  copyPublicFolder();
  // Start the webpack build
  return build(previousFileSizes);
})
.then(
  ({ stats, previousFileSizes, warnings }) => {
    if (warnings.length) {
      console.log(chalk.yellow('Compiled with warnings.\n'));
      console.log(warnings.join('\n\n'));
      console.log(
        '\nSearch for the ' +
          chalk.underline(chalk.yellow('keywords')) +
          ' to learn more about each warning.'
      );
      console.log(
        'To ignore, add ' +
          chalk.cyan('// eslint-disable-next-line') +
          ' to the line before.\n'
      );
    } else {
      console.log(chalk.green('Compiled successfully.\n'));
    }

    console.log('File sizes after gzip:\n');
    printFileSizesAfterBuild(
      stats,
      previousFileSizes,
      paths.appBuild,
      WARN_AFTER_BUNDLE_GZIP_SIZE,
      WARN_AFTER_CHUNK_GZIP_SIZE
    );
    console.log();
    buildServer();
  },
  err => {
    console.log(chalk.red('Failed to compile.\n'));
    printBuildError(err);
    process.exit(1);
  }
);

// Create the production build and print the deployment instructions.
function build(previousFileSizes) {
  console.log('Creating an optimized production build...');

  let compiler = webpack(config);
  return new Promise((resolve, reject) => {
    compiler.run((err, stats) => {
      if (err) {
        return reject(err);
      }
      const messages = formatWebpackMessages(stats.toJson({}, true));
      if (messages.errors.length) {
        // Only keep the first error. Others are often indicative
        // of the same problem, but confuse the reader with noise.
        if (messages.errors.length > 1) {
          messages.errors.length = 1;
        }
        return reject(new Error(messages.errors.join('\n\n')));
      }
      if (
        process.env.CI &&
        (typeof process.env.CI !== 'string' ||
          process.env.CI.toLowerCase() !== 'false') &&
        messages.warnings.length
      ) {
        console.log(
          chalk.yellow(
            '\nTreating warnings as errors because process.env.CI = true.\n' +
              'Most CI servers set it automatically.\n'
          )
        );
        return reject(new Error(messages.warnings.join('\n\n')));
      }
      return resolve({
        stats,
        previousFileSizes,
        warnings: messages.warnings,
      });
    });
  });
}

function copyPublicFolder() {
fs.copySync(paths.appPublic, paths.appBuild, {
  dereference: true,
  filter: file => file !== paths.appHtml,
});
}