bundling-with-optional-transpilation.js

let allSharedUtilities = sharedFilesToBuild.join(' + '),
    builds = [
        'scan', 'books', 'home', 'authenticate',
        { 
            module: 'reactStartup', 
            path: '( reactStartup + ' + allSharedUtilities + ' )', 
            saveTo: '../dist/reactStartup', 
            exclude: ['react', 'react-bootstrap'] 
        }
    ];

Promise.all([
    runBuild('dist-es5', { presets: ['es2015'] }),
    runBuild('dist-es6', undefined)
]).then(([buildOutputs]) => checkBundlesForDupsAndCreateConfigForBrowser(buildOutputs));

function runBuild(distFolder, babelOptions){
    let buildOutputs = {}
    return Promise
        .all(builds.map(createSingleBuild.bind(null, distFolder)))
        .then(results =>
            new Promise(function(res){
                results.forEach(({ saveTo, results }) => buildOutputs[saveTo.replace(`../${distFolder}`, distFolder)] = { modules: results.modules });

                gulp.src([`../${distFolder}/**/*-unminified.js`], { base: './' })
                    .pipe(gulpIf(babelOptions, lazypipe().pipe(babel, babelOptions).pipe(gulp.dest, '')()))
                    .pipe(gulpIf(babelOptions, gulpUglify()))
                    .pipe(gulpRename(function (path) {
                        path.basename = path.basename.replace(/-unminified$/, '-build');
                        console.log(`Finished compressing ${path.basename}`);
                    }))
                    .pipe(gulp.dest(''))
                    .on('end', () => res(buildOutputs));
            }).catch(err => console.log(err))
        )
}