Simple gulpfile.js

.babelrc

{
	"presets": [ "latest", "react" ],
	"plugins": [ "transform-runtime" ]
}

.eslintrc.yml

env:
  es6: true
  node: true
  browser: true
parserOptions:
  sourceType: module
parser: babel-eslint
plugins: [react]
rules:
  react/jsx-uses-react: warn
  react/jsx-uses-vars: warn
  react/jsx-no-undef: error
  no-alert: off
  no-array-constructor: off
  no-bitwise: off
  no-caller: off
  no-case-declarations: error
  no-catch-shadow: off
  no-class-assign: error
  no-cond-assign: error
  no-confusing-arrow: off
  no-console: warn
  no-const-assign: error
  no-constant-condition: error
  no-continue: off
  no-control-regex: error
  no-debugger: error
  no-delete-var: error
  no-div-regex: off
  no-dupe-class-members: error
  no-dupe-keys: error
  no-dupe-args: error
  no-duplicate-case: error
  no-duplicate-imports: off
  no-else-return: off
  no-empty: error
  no-empty-character-class: error
  no-empty-function: off
  no-empty-pattern: error
  no-eq-null: off
  no-eval: off
  no-ex-assign: error
  no-extend-native: off
  no-extra-bind: off
  no-extra-boolean-cast: error
  no-extra-label: off
  no-extra-parens: off
  no-extra-semi: error
  no-fallthrough: error
  no-floating-decimal: off
  no-func-assign: error
  no-implicit-coercion: off
  no-implicit-globals: off
  no-implied-eval: off
  no-inline-comments: off
  no-inner-declarations: error
  no-invalid-regexp: error
  no-invalid-this: off
  no-irregular-whitespace: warn
  no-iterator: off
  no-label-var: off
  no-labels: off
  no-lone-blocks: off
  no-lonely-if: off
  no-loop-func: off
  no-mixed-requires: off
  no-mixed-spaces-and-tabs: warn
  linebreak-style: off
  no-multi-spaces: warn
  no-multi-str: off
  no-multiple-empty-lines: off
  no-native-reassign: off
  no-negated-condition: off
  no-negated-in-lhs: error
  no-nested-ternary: off
  no-new: off
  no-new-func: off
  no-new-object: off
  no-new-require: off
  no-new-symbol: error
  no-new-wrappers: off
  no-obj-calls: error
  no-octal: error
  no-octal-escape: off
  no-param-reassign: off
  no-path-concat: off
  no-plusplus: off
  no-process-env: off
  no-process-exit: off
  no-proto: off
  no-redeclare: error
  no-regex-spaces: error
  no-restricted-globals: off
  no-restricted-imports: off
  no-restricted-modules: off
  no-restricted-syntax: off
  no-return-assign: off
  no-script-url: off
  no-self-assign: error
  no-self-compare: off
  no-sequences: off
  no-shadow: off
  no-shadow-restricted-names: off
  no-whitespace-before-property: off
  no-spaced-func: off
  no-sparse-arrays: error
  no-sync: off
  no-ternary: off
  no-trailing-spaces: warn
  no-this-before-super: error
  no-throw-literal: off
  no-undef: error
  no-undef-init: off
  no-undefined: off
  no-unexpected-multiline: error
  no-underscore-dangle: off
  no-unmodified-loop-condition: off
  no-unneeded-ternary: off
  no-unreachable: error
  no-unused-expressions: off
  no-unused-labels: error
  no-unused-vars: warn
  no-use-before-define: off
  no-useless-call: off
  no-useless-concat: off
  no-useless-constructor: off
  no-void: off
  no-var: warn
  no-warning-comments: warn
  no-with: off
  no-magic-numbers: off
  array-bracket-spacing: [warn, never]
  array-callback-return: off
  arrow-body-style: off
  arrow-parens: off
  arrow-spacing: [warn, {before: true, after: true}]
  accessor-pairs: off
  block-scoped-var: off
  block-spacing: off
  brace-style: off
  callback-return: off
  camelcase: off
  comma-dangle: [warn, always-multiline]
  comma-spacing: off
  comma-style: off
  complexity: [off, warn]
  computed-property-spacing: off
  consistent-return: off
  consistent-this: off
  constructor-super: error
  curly: off
  default-case: off
  dot-location: off
  dot-notation: off
  eol-last: warn
  eqeqeq: off
  func-names: off
  func-style: off
  generator-star-spacing: off
  global-require: off
  guard-for-in: off
  handle-callback-err: off
  id-length: off
  indent: [warn, tab]
  init-declarations: off
  jsx-quotes: off
  key-spacing: off
  keyword-spacing: off
  lines-around-comment: off
  max-depth: off
  max-len: off
  max-nested-callbacks: off
  max-params: off
  max-statements: off
  new-cap: off
  new-parens: off
  newline-after-var: off
  newline-before-return: off
  newline-per-chained-call: off
  object-curly-spacing: [warn, never]
  object-shorthand: off
  one-var: off
  one-var-declaration-per-line: off
  operator-assignment: off
  operator-linebreak: off
  padded-blocks: off
  prefer-arrow-callback: off
  prefer-const: warn
  prefer-reflect: off
  prefer-rest-params: off
  prefer-spread: off
  prefer-template: off
  quote-props: off
  quotes: [warn, single, {avoidEscape: true}]
  radix: off
  id-match: off
  id-blacklist: off
  require-jsdoc: off
  require-yield: off
  semi: [warn, never]
  semi-spacing: off
  sort-vars: off
  sort-imports: off
  space-before-blocks: warn
  space-before-function-paren: [warn, {anonymous: always, named: never}]
  space-in-parens: off
  space-infix-ops: off
  space-unary-ops: off
  spaced-comment: warn
  strict: [error, global]
  template-curly-spacing: off
  use-isnan: error
  valid-jsdoc: off
  valid-typeof: error
  vars-on-top: off
  wrap-iife: off
  wrap-regex: off
  yield-star-spacing: off
  yoda: off

gulpfile.js

// npm i --save-dev gulp gulp-autoprefixer gulp-babel del gulp-less lodash.once webpack
'use strict'

const gulp = require('gulp')

const autoprefixer = require('gulp-autoprefixer')
const babel = require('gulp-babel')
const del = require('del')
const less = require('gulp-less')
const plumber = require('gulp-plumber')
const webpack = require('webpack')

gulp.task('default', [ 'css', 'js:client', 'js:server' ])

gulp.task('css', () => gulp.src([ 'src/public/css/**/*.less', '!**/lib/**/*.*' ])
	.pipe(plumber())
	.pipe(less())
	.pipe(autoprefixer())
	.pipe(gulp.dest('cordova/www/css')))

const compiler = webpack(require('./webpack.config.js'))
const reporter = (err, stats) => console.log(stats.toString('normal'))
if (process.argv.includes('watch')) {
	gulp.task('js:public')
	compiler.watch({}, reporter)
} else {
	gulp.task('js:public', done => compiler.run((err, stats) => {
		reporter(err, stats)
		done(err)
	}))
}

gulp.task('js:server', () => gulp.src('src/main/**/*.js')
	.pipe(plumber())
	.pipe(babel())
	.pipe(gulp.dest('build')))

gulp.task('watch', [ 'default' ], function () {
	gulp.watch('src/public/css/**/*.less', [ 'css' ])
	gulp.watch('src/public/js/**/*.js', [ 'js:client' ])
	gulp.watch('src/main/**/*.js', [ 'js:server' ])
})

gulp.task('clean', () => Promise.all([
	del('cordova/www/css'),
	del('cordova/www/js'),
	del('build'),
]))

webpack.config.js

'use strict'

const glob = require('globby').sync
const path = require('path')
const webpack = require('webpack')
const NotifierPlugin = require('webpack-notifier')
const Visualizer = require('webpack-visualizer-plugin')

const entry = { }
glob([ 'src/public/js/**/*.js', '!**/lib/**/*.js' ])
	.forEach(f => entry[path.relative('src/public/js', f)] = path.resolve(process.cwd(), f)) // eslint-disable-line no-return-assign

const PROD = process.env.NODE_ENV == 'production'
const PROD_PLUGINS = [ new webpack.optimize.UglifyJsPlugin({
	comments: false,
	compress: { warnings: false },
	minimize: true,
}), new webpack.DefinePlugin({
	'process.env': {
		NODE_ENV: '"production"',
	},
}) ]
const DEV_PLUGINS = [ new Visualizer() ]

module.exports = {
	devtool: PROD ? '' : '#source-map',
	entry,
	output: {
		path: `${__dirname}/build/public/js`,
		filename: '[name]',
	},
	module: {
		loaders: [ {
			test: /\.js$/,
			loader: 'babel-loader',
			exclude: /node_modules/,
		}, {
			test: /\.scss$/,
			loader: 'style!css?modules&localIdentName=[name]_[local]_[hash:base64:5]!sass',
		} ],
	},
	plugins: [
		new webpack.optimize.CommonsChunkPlugin({
			name: 'common',
			filename: 'common.js',
			minChunks: 2,
		}),
		new NotifierPlugin({
			alwaysNotify: false,
		}),
	].concat(PROD ? PROD_PLUGINS : DEV_PLUGINS),
}