gulpfile.js

var gulp = require('gulp');
var concat = require('gulp-concat');
// var minify = require('gulp-minify');
var concatCss = require('gulp-concat-css');
var cleanCSS = require('gulp-clean-css');
var runSequence = require('run-sequence');
var del = require('del');
var babel = require('gulp-babel');
var uglify = require('gulp-uglify');
var pump = require('pump');
var minify = require('gulp-minify');
var minify = require("gulp-babel-minify");

gulp.task("minify-js", () =>
gulp.src("./files/js/compress.js")
    .pipe(minify({
      mangle: {
        keepClassName: true
      }
    }))
    .pipe(gulp.dest("./files/dist"))
);


gulp.task('minify-css', function () {
  return gulp.src('./files/dist/*.css')
      .pipe(cleanCSS())
      .pipe(gulp.dest('./files/dist'));
});


gulp.task('compress-css', function () {
  return gulp.src([
    'files/css/animate.css',
    'files/css/style.css',
    'files/css/font-awesome.min.css',
    'files/css/ionicons.css',
    'files/css/icomoon.css',
    // 'files/revolution/css/settings.css',
    // 'files/revolution/css/layers.css',
    // 'files/revolution/css/navigation.css',
    'files/css/owl.carousel.css',
    'files/css/lightcase.css',
    'files/css/billboard.css',
    'files/css/mqueries.css',
    'files/css/step-form-wizard-all.css',
    'files/css/jquery.mCustomScrollbar.min.css',
  ])
      .pipe(concatCss("compress.css"))
      .pipe(gulp.dest('files/dist/'));
});

gulp.task('compress-js', function () {
  return gulp.src(
      [
        'files/js/jquery_2_2_4.js',
        'files/js/jquery.easing.1.3.js',
        'files/js/jquery.visible.min.js',
        // 'files/revolution/js/jquery.themepunch.tools.min.js?rev=5.0',
        
        // 'files/revolution/js/jquery.themepunch.revolution.min.js?rev=5.0',
        // 'files/revolution/js/extensions/revolution.extension.slideanims.min.js',
        // 'files/revolution/js/extensions/revolution.extension.layeranimation.min.js',
        // 'files/revolution/js/extensions/revolution.extension.navigation.min.js',
        //
        // 'files/revolution/js/extensions/revolution.extension.video.min.js',
        // 'files/revolution/jss/extensions/revolution.extension.actions.min.js',
        // 'files/js/tweenMax.js',
        'files/js/jquery.backgroundparallax.min.js',
        'files/js/jquery.isotope.min.js',
        'files/js/jquery.imagesloaded.min.js',
        // 'files/js/jquery.owl.carousel.js',
        // 'files/js/jquery.lightcase.min.js',
        'files/js/script.js',
        'files/js/jquery.ajaxchimp.min.js',
        // 'files/js/jquery.countdown.min.js',
        'files/js/social.js',
        //
        'files/js/jquery.countdown.js',
        'files/js/step-form-wizard.min.js',
        'files/js/jquery.mCustomScrollbar.concat.min.js',
        //newly commented 05.03
        
        'files/js/d3.js',
        
        //newly commented 05.03 
        
        'files/js/custom.js',
        'files/js/billboard.js',
        'files/js/chart.js',
        
        //newly commented 05.03 end
        'files/js/index.js'
      ])
      .pipe(concat('compress.js'))
      .pipe(gulp.dest('./files/js'));
});

gulp.task('clean:dist', function () {
  return del.sync('files/dist');
});

gulp.task('css', function (callback) {
  runSequence('compress-css', 'minify-css', callback);
});

gulp.task('default', function (callback) {
  runSequence('clean:dist', 'compress-css', 'minify-css', 'compress-js',
      'minify-js',
      callback
  )
});