Gulp setup

.eslintrc.json

{
  "root" : true,
  "extends": "eslint:recommended",
  "globals": {
    "Drupal": true,
    "drupalSettings": true,
    "drupalTranslations": true,
    "domready": true,
    "jQuery": true,
    "_": true,
    "matchMedia": true,
    "Backbone": true,
    "Modernizr": true,
    "CKEDITOR": true
  }
}

.stylilintrc

{
  "plugins": [
    "stylelint-scss"
  ],
  "extends": "stylelint-config-standard",
  "rules": {
    "at-rule-no-unknown": null,
    "scss/at-rule-no-unknown": true,
    "number-leading-zero": null,
    "selector-list-comma-newline-after": null
  }
}

gulpfile.js

const gulp = require('gulp')
const browserify = require('browserify')
const environments = require('gulp-environments');
const babelify = require('babelify');
// const rename = require('gulp-rename')
const sourcemaps = require('gulp-sourcemaps');
const sass = require('gulp-sass')
// const eslint = require('gulp-eslint')
// const eslintify = require('eslintify')
const gulpStylelint = require('gulp-stylelint')
const cleanCSS = require('gulp-clean-css')
const fontAwesome = require('node-font-awesome')
const autoprefixer = require('gulp-autoprefixer')
// const source = require('vinyl-source-stream')
const buffer = require('vinyl-buffer')
// const livereload = require('gulp-livereload')
// const plumber = require('gulp-plumber')
// const plumberNotifier = require('gulp-plumber-notifier')
const uglify = require('gulp-uglify')
const imagemin = require('gulp-imagemin')
const tap = require('gulp-tap')
// const exec = require('gulp-exec')
const gutil = require('gulp-util')
const merge = require('merge-stream')
const clean = require('gulp-clean')

var development = environments.development
var production = environments.production

var SassPath = [
  './scss/**/*.+(scss|sass)'
]

gulp.task('scss', function () {
  gutil.log('Compiling scss on ' + environments.current().$name + ' env.')

  return gulp.src(SassPath)
    .pipe(development(sourcemaps.init()))
    .pipe(gulpStylelint({
      failAfterError: production(),
      reporters: [
        {formatter: 'string', console: true}
      ]
    }))
    .pipe(sass(
      {
        includePaths: [
          fontAwesome.scssPath
        ],
        style: development ? 'expanded' : 'compressed'
      }
    ).on('error', sass.logError))
    .pipe(autoprefixer({
      browsers: ['last 2 versions'],
      cascade: false
    }))
    .pipe(development(sourcemaps.write()))
    .pipe(production(cleanCSS()))
    .pipe(gulp.dest('./assets/css'))
})

gulp.task('scripts', function () {
  return gulp.src('./js/**/*.js', {read: false})
    .pipe(tap(function (file) {
      gutil.log('bundling ' + file.path)
      var b = browserify(file.path, {})
        .transform('browserify-shim')
        .transform(babelify, {
          'presets': ['es2015'],
          sourceMaps: development
        })
      file.contents = b.bundle()
    }))
    .pipe(buffer())
    .pipe(development(sourcemaps.init({loadMaps: true})))
    .pipe(production(uglify()))
    .pipe(development(sourcemaps.write()))
    .pipe(gulp.dest('./assets/js/'))
})

gulp.task('fonts', function () {
  return merge(
//     gulp.src(fontAwesome.fonts).pipe(gulp.dest('./assets/fonts/FontAwesome')),
    gulp.src('./fonts/Lato2OFL/**/*.+(ttf|woff|eot|svg)').pipe(gulp.dest('./assets/fonts/Lato'))
  )
})

gulp.task('images', function () {
  gulp.src('node_modules/slick-carousel/slick/ajax-loader.gif')
    .pipe(gulp.dest('./web/assets/images/slick'))
  gulp.src('./images/**/*')
    .pipe(imagemin())
    .pipe(gulp.dest('./assets/images'))
})

gulp.task('watch', ['scss', 'scripts', 'fonts', 'images', 'libs'], function () {
  gulp.watch(SassPath, ['scss']);
  gulp.watch('./js/**/*.js', ['scripts']);
  gulp.watch('./images/**/*', ['images']);
  gulp.watch('package.json', ['libs']);
});

gulp.task('eslint', function () {
  return (gulp.src('js/index.js'))
});

gulp.task('clean', function () {
  return gulp.src('./assets', {read: false})
    .pipe(clean())
});

gulp.task('libs', function () {
//   return merge(
//     gulp.src('node_modules/superfish/dist/**/*')
//       .pipe(gulp.dest('./assets/libs/superfish')),
//     gulp.src('node_modules/select2/dist/**/*')
//       .pipe(gulp.dest('./assets/libs/select2'))
//   );
});

gulp.task('set-prod', production.task)
gulp.task('build', ['set-prod', 'scss', 'scripts', 'fonts', 'images', 'libs'])

gulp.task('default', ['watch'])

package.json

{
  "name": "GreenLeaves",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "clique.digital agency",
  "license": "ISC",
  "browserify-shim": {},
  "devDependencies": {
    "babel-preset-es2015": "^6.24.1",
    "babelify": "^7.3.0",
    "browserify": "^14.4.0",
    "browserify-shim": "^3.8.14",
    "eslint": "^4.15.0",
    "eslint-config-standard": "^10.2.1",
    "eslint-plugin-import": "^2.8.0",
    "eslint-plugin-node": "^5.2.1",
    "eslint-plugin-promise": "^3.6.0",
    "eslint-plugin-standard": "^3.0.1",
    "gulp": "^3.9.1",
    "gulp-autoprefixer": "^4.0.0",
    "gulp-clean": "^0.3.2",
    "gulp-clean-css": "^3.7.0",
    "gulp-environments": "^0.1.2",
    "gulp-exec": "^2.1.3",
    "gulp-imagemin": "^3.3.0",
    "gulp-livereload"`: "^3.8.1",
    "gulp-plumber": "^1.1.0",
    "gulp-plumber-notifier": "0.0.3",
    "gulp-pug": "^3.3.0",
    "gulp-rename": "^1.2.2",
    "gulp-sass": "^3.1.0",
    "gulp-sourcemaps": "^2.6.1",
    "gulp-stylelint": "^4.0.0",
    "gulp-tap": "^1.0.1",
    "gulp-uglify": "^3.0.0",
    "stylelint": "^8.2.0",
    "stylelint-config-standard": "^17.0.0",
    "stylelint-scss": "^2.1.0",
    "vinyl-buffer": "^1.0.0",
    "vinyl-source-stream": "^1.1.0"
  },
  "dependencies": {
    "eslint-config-standart": "^0.2.0",
  }
}