gulpfile.js

const gulp        = require('gulp');
const browserSync = require('browser-sync');
const sass = require('gulp-sass')(require('sass'));
const rename = require("gulp-rename");
const autoprefixer = require('gulp-autoprefixer');
const cleanCSS = require('gulp-clean-css');
const imagemin = require('gulp-imagemin');
const htmlmin = require('gulp-htmlmin');

// Static server
gulp.task('server', function() {
    browserSync.init({
        server: {
            baseDir: 'dist'
        }
    });

    gulp.watch('src/*.html').on('change', browserSync.reload);
});

gulp.task('styles', function() {
    return gulp.src('src/sass/**/*.+(scss|+sass)')
        .pipe(sass({outputStyle: 'compressed'}).on('error', sass.logError))
        .pipe(rename({
            prefix: "",
            suffix: ".min",
          }))
        .pipe(autoprefixer())
        .pipe(cleanCSS({compatibility: 'ie8'}))
        .pipe(gulp.dest('dist/css'))
        .pipe(browserSync.stream());
});

gulp.task('watch', function() {
    gulp.watch('src/sass/**/*.+(scss|sass|css)', gulp.parallel('styles'));
    gulp.watch('src/*.html').on('change', gulp.parallel('html'));
});

gulp.task('html', function() {
    return gulp.src('src/*.html')
    .pipe(htmlmin({ collapseWhitespace: true }))
    .pipe(gulp.dest('dist/'));
});

gulp.task('scripts', function() {
    return gulp.src('src/js/**/*.js')
    .pipe(gulp.dest('dist/js'));
});

gulp.task('fonts', function() {
    return gulp.src('src/fonts/**/*')
    .pipe(gulp.dest('dist/fonts'));
});

gulp.task('icons', function() {
    return gulp.src('src/icons/**/*')
    .pipe(gulp.dest('dist/icons'));
});

gulp.task('mailer', function() {
    return gulp.src('src/mailer/**/*')
    .pipe(gulp.dest('dist/mailer'));
});

gulp.task('images', function() {
    return gulp.src('src/img/**/*')
    .pipe(imagemin())
    .pipe(gulp.dest('dist/img'));
});

gulp.task('default', gulp.parallel('watch', 'server', 'styles', 'scripts', 'fonts', 'icons', 'mailer', 'html', 'images'));