Gulpfile with gulp-bem-presets

gulpfile.js

const gulp = require('gulp');
const Builder = require('gulp-bem-bundle-builder');
const bundler = require('gulp-bem-bundler-fs');
const nodemon = require('gulp-nodemon');
const merge = require('merge2');
const debug = require('gulp-debug');
const babel = require('gulp-babel');
const uglify = require('gulp-uglify');
const gulpif = require('gulp-if');
const concat = require('gulp-concat');

const env = process.env.NODE_ENV

const builder = Builder({
  levels: [
    'bem/libs/bem-core/common.blocks',
    'bem/libs/bem-core/desktop.blocks',
    'bem/libs/bem-components/common.blocks',
    'bem/libs/bem-components/desktop.blocks',
    'bem/libs/bem-components/design/common.blocks',
    'bem/libs/bem-components/design/desktop.blocks',
    'bem/libs/bem-forms/common.blocks',
    'bem/libs/bem-animations/@common',
    'bem/libs/bem-animations/@bem-core-v4',
    'bem/blocks/@common/',
    'bem/blocks/@desktop/',
  ],
  techMap: {
    bemtree: ['bemtree.js'],
    bemhtml: ['bemhtml.js'],
    js: ['js', 'vanilla.js', 'source.js', 'browser.js'],
    css: ['styl', 'css', 'post.css']
  }
});

gulp.task('build', () => {
    return bundler('bem/bundles/*')
    .pipe(builder({
      
      // Styles
      css: bundle =>
        require('gulp-bem-preset-css')(bundle, {svgPaths: ['bem/icons']}),
      
      // client JS, BEMTREE, BEMHTML
      js: bundle => merge(
        require('gulp-bem-preset-browserjs')(bundle, {includePaths: ['bem']}),
        require('gulp-bem-preset-bemtree')(bundle, {ym: true}),
        require('gulp-bem-preset-bemhtml')(bundle, {ym: true, engine: {elemJsInstances: true}})
      )
      .pipe(gulpif(env === 'production', babel({ presets: ['es2015'], compact: false })))
      .pipe(gulpif(env === 'production', uglify()))
      .pipe(concat(bundle.name + '.min.js')),
      
      // server BEMTREE
      bemtree: bundle =>
        require('gulp-bem-preset-bemtree')(bundle)
        .pipe(gulp.dest('./bem/server/')),
      
      // server BEMHTML
      bemhtml: bundle =>
        require('gulp-bem-preset-bemhtml')(bundle)
        .pipe(gulp.dest('./bem/server/'))
   }))
   .on('error', console.error)
   .pipe(debug())
   .pipe(gulp.dest('./public/bundles/'));
});

gulp.task('default', gulp.series('build'));