function bundle_js(bundler) {
  return bundler
    .bundle()
    .pipe(plumber({ errorHandler: onError }))
    .pipe(source("main.js"))
    .pipe(buffer())
    .pipe(rename(js_destFile))
    .pipe(gulp.dest(js_destFolder))
    .pipe(gulp.dest(js_destFolder_CX))
    .pipe(notify(onSuccess("JS")));
}
/*.less";
let less_srcFile = app + "styles/etherwallet-master.less";
let less_destFolder = dist + "css";
let less_destFolder_CX = dist_CX + "css";
let less_destFile = "etherwallet-master.css";
let less_destFileMin = "etherwallet-master.min.css";

gulp.task("styles", function() {
  return (
    gulp
      .src(less_srcFile)
      .pipe(plumber({ errorHandler: onError }))
      .pipe(less({ compress: false }))
      .pipe(
        autoprefixer({
          browsers: ["last 4 versions", "iOS > 7"],
          remove: false
        })
      )
      .pipe(rename(less_destFile))
      //.pipe( gulp.dest   (  less_destFolder                                         )) // unminified css
      //.pipe( gulp.dest   (  less_destFolder_CX                                      )) // unminified css
      .pipe(cssnano({ autoprefixer: false, safe: true }))
      .pipe(rename(less_destFileMin))
      .pipe(gulp.dest(less_destFolder))
      .pipe(gulp.dest(less_destFolder_CX))
      .pipe(notify(onSuccess("Styles")))
  );
});

// js: Browserify
let js_watchFolder = app + "scripts/*