Simple Gulp boilerplate

gulpfile.js

/**
 * Gulp boilerplate
 * 
 * Requirements:
 *   - NodeJS (https://nodejs.org/)
 *   - Gulp (http://gulpjs.com/)
 * 
 * Start new project:
 * ```
 *     mkdir project-name
 *     cd project-name
 *     npm init
 *     npm install --save-dev gulp
 * ```
 * 
 * Install each plugin in project folder with:
 * ```
 *     npm install --save-dev {plugin-name}
 * ```
 * 
 * Configured plugin:
 *   - del
 *   - gulp-rename
 *   - gulp-html-minify
 *   - gulp-sitemap
 *   - gulp-save
 *   - gulp-imagemin
 *   - gulp-less
 *   - gulp-sass
 *   - gulp-clean-css
 *   - gulp-concat
 *   - gulp-uglify
 */

const gulp = require('gulp');
const rename = require("gulp-rename");
const htmlminify = require('gulp-html-minify'); // Minify HTML.
const del = require('del');                     // Clean production folder.
const sitemap = require('gulp-sitemap');        // Generate sitemap.
const save = require('gulp-save');              // Generate sitemap.
const imagemin = require('gulp-imagemin');      // Optimize images.
const less = require('gulp-less');              // Compile LESS files from /less into /css
const sass = require('gulp-sass');              // Compile Sass into standard CSS.
const cleanCSS = require('gulp-clean-css');     // Minify compiled CSS
const concat = require('gulp-concat');          // Concat and minify javascripts.
const uglify = require('gulp-uglify');          // Concat and minify javascripts.

// Destination folders: EDIT THIS AS YOU LIKE.
const DIST = 'dist';
const SITE_URL = 'http://my-domain.com';

// Clean production folder.
gulp.task('clean', function() {
    console.log('"' + DIST + '" folder is empty!');
    return del(DIST);
});

// Minify HTML.
gulp.task('html' , function(){
    gulp.src('src/*.html')
        .pipe(htmlminify())
        .pipe(gulp.dest(DIST))
});

// Generate sitemap.
gulp.task('sitemap', function() {
    gulp.src('src/*.html', {read: false})
        .pipe(save('before-sitemap'))
        .pipe(sitemap({siteUrl: SITE_URL}))
        .pipe(gulp.dest(DIST))
        .pipe(save.restore('before-sitemap'))
});

// Copy html files to production folder.
gulp.task('copy', function() {
    gulp.src('src/*.html')
        .pipe(gulp.dest(DIST))
})

// Optimize images.
gulp.task('imagemin', function() {
    gulp.src('src/images/*')
        .pipe(imagemin())
        .pipe(gulp.dest(DIST + '/images'))
});

// Compile Sass into standard CSS.
gulp.task('sass', function() {
    return gulp.src('src/sass/*.scss')
        .pipe(sass().on('error', sass.logError))
        .pipe(gulp.dest('src/css'))
});

// Compile LESS files from /less into /css
gulp.task('less', function() {
    gulp.src('src/less/*.less')
        .pipe(less())
        .pipe(gulp.dest('/css'))
});

// Concat and minify javascripts.
// Destination file name: 'main.min.js'
gulp.task('js', function() {
    gulp.src('src/js/*.js')
        .pipe(concat('main.js'))
        .pipe(uglify())
        .pipe(rename({ suffix: '.min' }))
        .pipe(gulp.dest(DIST + '/js'))
});

// Minify compiled CSS (destination file name: 'style.min.css')
gulp.task('css', function() {
    return gulp.src('src/css/*.css')
        .pipe(cleanCSS({ compatibility: 'ie8' }))
        .pipe(concat('style.css'))
        .pipe(rename({ suffix: '.min' }))
        .pipe(gulp.dest(DIST + '/css'))
});

// Run all tasks.
gulp.task('default', ['clean', 'sitemap', 'copy', 'imagemin', 'less', 'sass', 'css', 'js']);

// Watch for changes.
gulp.task('dev', function() {
    gulp.watch('src/js/*.js', ['js'])
    gulp.watch('src/css/*.css', ['css'])
    gulp.watch('src/sass/*.scss', ['sass', 'css'])
    gulp.watch('src/less/*.less', ['less', 'css'])
    gulp.watch('src/*.html', ['html'])
});