fix js task, switch to env Babel preset

.babelrc

@@ -1,3 +1,3 @@
 {
-  "presets": ["es2015"]
-}
+  "presets": ["env"]
+}

gulpfile.babel.js

@@ -12,6 +12,10 @@ import yaml from 'js-yaml'
 import chalk from 'chalk'
 import yargs from 'yargs'
 
+// Required for mixing old and ES6+ js with ugify-js 3
+import uglifyjs from 'uglify-es'
+import composer from 'gulp-uglify/composer'
+
 // Get all the configs: `pkg` and `site`
 import pkg from './package'
 
@@ -21,6 +25,9 @@ const site = yaml.safeLoad(fs.readFileSync('./_config.yml'))
 const spawn = require('child_process').spawn
 const $ = require('gulp-load-plugins')()
 
+// Custom minify
+const minify = composer(uglifyjs, console)
+
 // Handle errors
 const onError = error => {
     console.log($.util.colors.red('\nYou fucked up:', error.message, 'on line', error.lineNumber, '\n'))
@@ -204,7 +211,7 @@ export const criticalCss = done => {
 //
 // Scripts
 //
-const js = () =>
+export const js = () =>
     src([
         SRC + '/_assets/js/kremalicious3.js',
         'node_modules/picturefill/dist/picturefill.js'
@@ -213,7 +220,7 @@ const js = () =>
     .pipe($.include({
         includePaths: ['node_modules', SRC + '/_assets/js']
     })).on('error', onError)
-    .pipe($.if(isProduction, $.uglify())).on('error', onError)
+    .pipe($.if(isProduction, minify())).on('error', onError)
     .pipe($.if(!isProduction, $.sourcemaps.write()))
     .pipe($.if(isProduction, $.header(BANNER, {pkg})))
     .pipe($.rename({suffix: '.min'}))

package.json

@@ -53,7 +53,7 @@
     "acorn": "^5.1.2",
     "autoprefixer": "^7.1.4",
     "babel-core": "^6.26.0",
-    "babel-preset-es2015": ">=6.24.0",
+    "babel-preset-env": "^1.6.0",
     "browser-sync": "^2.18.13",
     "chalk": "^2.1.0",
     "concurrent-transform": ">=1.0.0",
@@ -82,6 +82,7 @@
     "gulp-uglify": ">=1.2.0",
     "js-yaml": "^3.9.1",
     "request": ">=2.81.0",
+    "uglify-es": "^3.0.28",
     "xo": "^0.18.2",
     "yargs": "^8.0.2"
   },