gulpfile.js

let gulp = require('gulp');
let sass = require('gulp-sass');
let browserify = require('browserify');
let source = require('vinyl-source-stream');
let gutil = require('gutil');
let react = require('gulp-react');

let libs = ['react', 'react-dom', 'redux', 'react-redux'];

gulp.task('app', function () {
    let bundler = browserify({entries: './src/js/bootstrap.jsx', extensions: ['.jsx'], debug: true});

    libs.forEach(function(lib) {
        bundler.external(require.resolve(lib, { expose: lib }));
    });

    bundler.transform('babelify', {presets: ['es2015', 'react']})
        .bundle()
        .on('error', gutil.log)
        .pipe(source('app.js'))
        .pipe(gulp.dest('dist/js'));
});

gulp.task('libs', function () {
    let bundler = browserify({
        debug: false
    });

    libs.forEach(function(lib) {
        bundler.require(lib);
    });

    bundler.bundle()
        .pipe(source('libs.js'))
        .on('error', gutil.log)
        .pipe(gulp.dest('dist/js'));
});

gulp.task('sass', () => {
    gulp.src('src/scss/*.scss')
        .pipe(sass())
        .pipe(gulp.dest('dist/css'));
});

gulp.task('static', () => {
    gulp.src('src/static/**')
        .pipe(gulp.dest('dist/'));
});

gulp.task('build', ['static', 'libs', 'app', 'sass']);

gulp.task('watch', ['build'], () => {
    gulp.watch('src/scss/*.scss', ['sass']);
    gulp.watch(['src/**/*.js', 'src/**/*.jsx'], ['app']);
});