gulpfile.js

var gulp = require('gulp');

var browserify = require('browserify');
var watchify = require('watchify');
var babelify = require('babelify');

var source = require('vinyl-source-stream');
var buffer = require('vinyl-buffer');
var merge = require('utils-merge');

var rename = require('gulp-rename');
var uglify = require('gulp-uglify');
var sourcemaps = require('gulp-sourcemaps');
var babel = require('gulp-babel');


/* nicer browserify errors */
var gutil = require('gulp-util');
var chalk = require('chalk');

function map_error(err) {
    if (err.fileName) {
        // regular error
        gutil.log(chalk.red(err.name)
            + ': '
            + chalk.yellow(err.fileName.replace(__dirname + '/public/js/', ''))
            + ': '
            + 'Line '
            + chalk.magenta(err.lineNumber)
            + ' & '
            + 'Column '
            + chalk.magenta(err.columnNumber || err.column)
            + ': '
            + chalk.blue(err.description))
    } else {
        // browserify error..
        gutil.log(chalk.red(err.name)
            + ': '
            + chalk.yellow(err.message))
    }

    //this.end()
}
/* */

gulp.task('watchify', function () {
    var args = merge(watchify.args, { debug: true });
    var bundler = watchify(browserify('./public/app.jsx', args)).transform(babelify, {presets: ["es2015", "react"]});
    bundle_js(bundler);

    bundler.on('update', function () {
        bundle_js(bundler)
    })
});

function bundle_js(bundler) {
    return bundler.bundle()
        .on('error', map_error)
        .pipe(source('bundle.js'))
        .pipe(buffer())
        .pipe(gulp.dest('public/build'))
        .pipe(rename('bundle.min.js'))
        .pipe(sourcemaps.init({ loadMaps: false }))
        // capture sourcemaps from transforms
        .pipe(uglify())
        .pipe(sourcemaps.write('.'))
        .pipe(gulp.dest('public/build'))
}

// Without watchify
gulp.task('browserify', function () {
    var bundler = browserify('./public/app.jsx', { debug: false }).transform(babelify, {presets: ["es2015", "react"]});
    return bundle_js(bundler);
});

gulp.task('babel', () => {
    
    return gulp.src('./public/js/**/*.js')
    .pipe(babel({
        presets: ['es2015']
    }))
    .pipe(gulp.dest('public/lib'));

});

// Without sourcemaps
gulp.task('browserify-production', function () {
    var bundler = browserify('./public/app.js').transform(babelify, {presets: ["es2015", "react"]});

    return bundler.bundle()
        .on('error', map_error)
        .pipe(source('bundle.js'))
        .pipe(buffer())
        .pipe(rename('bundle.min.js'))
        .pipe(uglify())
        .pipe(gulp.dest('old_public/build'))
});