Bring in babel for modern JS

gulpfile.js

@@ -3,6 +3,7 @@
 
 var gulp = require("gulp");
 var concat = require("gulp-concat");
+var babel = require("gulp-babel");
 var postcss = require("gulp-postcss");
 var rename = require("gulp-rename");
 var sass = require("gulp-sass");
@@ -35,8 +36,13 @@ function javascript() {
   return gulp
     .src(src_path + "scripts/[!_]*.js", { since: gulp.lastRun(javascript) })
     .pipe(sourcemaps.init())
-    .pipe(concat("scripts/main.js"))
+    .pipe(
+      babel({
+        presets: ["@babel/env"],
+      })
+    )
     .pipe(uglify())
+    .pipe(concat("scripts/main.js"))
     .pipe(sourcemaps.write(""))
     .pipe(gulp.dest(dest_path));
 }

package.json

@@ -14,5 +14,10 @@
     "postcss": "^7.0.36",
     "postcss-easy-import": "^3.0.0",
     "sass": "^1.36.0"
+  },
+  "devDependencies": {
+    "@babel/core": "^7.14.8",
+    "@babel/preset-env": "^7.14.8",
+    "gulp-babel": "^8.0.0"
   }
 }