Replaced gulp-uglify with uglify-es

gulpfile.babel.js

@@ -13,14 +13,12 @@ import istanbul from 'gulp-babel-istanbul';
 import coveralls from 'gulp-coveralls';
 import jsdoc from 'gulp-jsdoc3';
 import sourcemaps from 'gulp-sourcemaps';
-import uglify from 'gulp-uglify';
 import rename from 'gulp-rename';
 import sass from 'gulp-sass';
 import sassModuleImporter from 'sass-module-importer'; // eslint-disable-line import/no-unresolved, import/extensions
 import cleanCss from 'gulp-clean-css';
 import autoprefixer from 'gulp-autoprefixer';
 import stylelint from 'gulp-stylelint';
-import babel from 'gulp-babel';
 import webpack from 'webpack';
 import WebpackDevServer from 'webpack-dev-server';
 import open from 'open';
@@ -29,9 +27,14 @@ import yargs from 'yargs';
 import ftp from 'vinyl-ftp';
 import url from 'url';
 
+import uglifyes from 'uglify-es';
+import composer from 'gulp-uglify/composer';
+
 import webpackConfig from './webpack.config';
 import rollupConfig from './rollup.config';
 
+const uglify = composer(uglifyes, console);
+
 const packageJson = require('./package.json');
 
 gulp.task('default', done =>
@@ -173,9 +176,6 @@ gulp.task('build:js', () =>
   }).then(() =>
     gulp.src(packageJson.main)
       .pipe(sourcemaps.init({ loadMaps: true }))
-      .pipe(babel({
-        presets: ['env'],
-      }))
       .pipe(uglify(uglifyConfig))
       .pipe(rename({ suffix: '.min' }))
       .pipe(sourcemaps.write('.'))

package.json

@@ -61,7 +61,6 @@
     "file-system": "^2.2.2",
     "gulp": "^3.9.1",
     "gulp-autoprefixer": "^3.1.1",
-    "gulp-babel": "^7.0.0",
     "gulp-babel-istanbul": "^1.6.0",
     "gulp-clean-css": "^3.0.3",
     "gulp-coveralls": "^0.1.4",
@@ -96,7 +95,8 @@
     "vinyl-ftp": "^0.6.0",
     "webpack": "^2.2.1",
     "webpack-dev-server": "^2.4.1",
-    "yargs": "^6.6.0"
+    "yargs": "^6.6.0",
+    "uglify-es": "^3.3.7"
   },
   "dependencies": {
     "jszip": "^3.1.4",