gulpfile.js

const {series, watch, src, dest, parallel} = require('gulp');
const pump = require('pump');

// gulp plugins and utils
var livereload = require('gulp-livereload');
var sass = require('gulp-sass');
var zip = require('gulp-zip');
var concat = require('gulp-concat');
var rename = require('gulp-rename');
var uglify = require('gulp-uglify');
var beeper = require('beeper');

function serve(done) {
    livereload.listen();
    done();
}

const handleError = (done) => {
    return function (err) {
        if (err) {
            beeper();
        }
        return done(err);
    };
};

function hbs(done) {
    pump([
        src(['*.hbs', 'partials/**/*.hbs', '!node_modules/**/*.hbs']),
        livereload()
    ], handleError(done));
}

sass.compiler = require('node-sass');

function css(done) {
    pump([
        src('./assets/main/sass/*.scss', {sourcemaps: true}),
        sass({outputStyle: 'compressed'}).on('error', sass.logError),
        dest('assets/main/css', {sourcemaps: './'}),
        livereload()
    ], handleError(done));
}

function js(done) {
    var jsAssetsDirPath = "./assets/main/js/";
    var files = [
        'jquery.min.js',
        'jquery.scrollex.min.js',
        'jquery.scrolly.min.js',
        'browser.min.js',
        'breakpoints.min.js',
        'util.js',
        'main.js'
    ]
    pump([
        src(files.map( file => jsAssetsDirPath + file )),
        concat('bundle.js'),
        uglify(),
        dest('assets/main/js')
    ], handleError(done));
}

function zipper(done) {
    var targetDir = 'dist/';
    var themeName = require('./package.json').name;
    var filename = themeName + '.zip';

    pump([
        src([
            '**',
            '!node_modules', '!node_modules/**',
            '!dist', '!dist/**'
        ]),
        zip(filename),
        dest(targetDir)
    ], handleError(done));
}

const cssWatcher = () => watch('./assets/main/sass/**/**', css);
const hbsWatcher = () => watch(['*.hbs', 'partials/**/*.hbs', '!node_modules/**/*.hbs'], hbs);
const watcher = parallel(cssWatcher, hbsWatcher);
const build = series(css, js);
const dev = series(build, serve, watcher);

exports.build = build;
exports.zip = series(build, zipper);
exports.default = dev;