gulp 4, gulpfile (pug, sass, autoprefixer, browser-sync)

gulpfile.js

/*!
 * eutheme.com
 * 29.01.2019
 */

const {src,dest,parallel,watch} = require('gulp');
const pug = require('gulp-pug');
const sass = require('gulp-sass');
const prefix = require('gulp-autoprefixer');
const server = require('browser-sync').create();

function html() {
    return src('sources/pug/*.pug')
        .pipe(pug({
            pretty: true
        }))
        .pipe(dest('public'))
}
function css() {
    return src('sources/scss/*.scss')
        .pipe(sass({
            outputStyle: 'expanded'
        }))
        .pipe(prefix({
            browsers: ['last 2 versions'],
            cascade: false
        }))
        .pipe(dest('public/css'))
}
function yenile(done) {
    server.reload()
    done()
}
function izle() {
    watch('sources/pug/**/*.pug',parallel(html,yenile));
    watch('sources/scss/**/*.scss',parallel(css,yenile));
}
function serve() {
    server.init({
        server: {
            baseDir: 'public'
        }
    })
}

exports.default = parallel(serve,izle);