Local inline project sample gulpfile.js

gulpfile.js

const { series, src, dest, watch } = require('gulp');
const babel = require('gulp-babel');
const rename = require('gulp-rename');
const uglify = require('gulp-uglify');
const concat = require('gulp-concat');
const sass = require('gulp-sass');
const cleanCSS = require('gulp-clean-css');

function scripts() {
	return src([
			'js/*.js'
		])
		.pipe(babel({presets: ['@babel/preset-env']}))
		// .pipe(concat('bulk_scripts.js'))
		.pipe(dest('./js/dist/')) 
		.pipe(uglify())
		.pipe(rename({suffix: '.min'}))
		.pipe(dest('./js/dist/')) 
}

function scss() {
	return src([
			'css/*.scss'
		])
		.pipe(sass())
		// .pipe(concat('bulk_css.css'))
		.pipe(dest('./css/dist/'))
		.pipe(cleanCSS())
		.pipe(rename({suffix: '.min'}))
		.pipe(dest('./css/dist/'))
}

function watcher() {
	watch('js/*.js', series(scripts));
	watch('css/*.scss', series(scss));
}

exports.build = series(scripts, scss);
exports.default = watcher;