@computerrock/toolchain-react-app/scripts/build.js

The Formation Framework template for starting react app project.

'use strict';

// set env
process.env.BABEL_ENV = 'production';
process.env.NODE_ENV = 'production';

// exit on unhandled rejections
process.on('unhandledRejection', err => {
    throw err;
});

// load env variables
require('../config/env');

// @remove-on-eject-begin
// Do the pre-flight dependency check (only happens before eject).
const verifyPackageTree = require('./utils/verifyPackageTree');
if (process.env.SKIP_PREFLIGHT_CHECK !== 'true') {
    verifyPackageTree();
}
// @remove-on-eject-end

const fs = require('fs-extra');
const chalk = require('chalk');
const webpack = require('webpack');
const checkRequiredFiles = require('@computerrock/react-dev-utils/checkRequiredFiles');
const formatWebpackMessages = require('@computerrock/react-dev-utils/formatWebpackMessages');
const FileSizeReporter = require('@computerrock/react-dev-utils/FileSizeReporter');
const printBuildError = require('@computerrock/react-dev-utils/printBuildError');
const paths = require('../config/paths');
const createWebpackConfig = require('../config/webpack.config');

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

// set bundle size limits
const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024;
const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024;

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

measureFileSizesBeforeBuild(paths.appBuild)
    .then(previousFileSizes => {
        fs.emptyDirSync(paths.appBuild);
        copyPublicFolder();
        return build(previousFileSizes);
    })
    .then(
        ({stats, previousFileSizes, warnings}) => {
            if (warnings.length) {
                console.log(chalk.yellow('Compiled with warnings.\n'));
                console.log(warnings.join('\n\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,
            );
        },
        err => {
            console.log(chalk.red('Failed to compile.\n'));
            printBuildError(err);
            process.exit(1);
        },
    );

function build(previousFileSizes) {
    console.log('Creating an optimized production build...');

    let compiler = webpack(createWebpackConfig('production'));
    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,
    });
}