gulpfile.js

var gulp = require('gulp');
var sass = require('gulp-sass');
var autoprefixer = require('gulp-autoprefixer');
var browserSync = require('browser-sync');
var del = require('del');
var imagemin = require('gulp-imagemin');
var pngquant = require('imagemin-pngquant');
var cache = require('gulp-cache');

gulp.task('sass', function() {
	return gulp.src(['app/sass/**/*.sass', 'app/sass/**/*.scss'])
	.pipe(sass({outputStyle: 'expanded'}).on('error', sass.logError))
	.pipe(autoprefixer({
		browsers: ['last 15 versions', '> 1%', 'ie 8', 'ie 7'],
		cascade: false
	}))
	.pipe(gulp.dest('app/css'))
	.pipe(browserSync.reload({stream: true}))
});

gulp.task('browser-sync', function() {
	browserSync({
		server: {
			baseDir: 'app'
		},
		notify: false,
		//tunnel: true,
		//tunnel: "ptoj"
	})
});

gulp.task('clean', function() {
	return del.sync('dist');
});

gulp.task('clear', function() {
	return cache.clearAll();
});

gulp.task('img', function() {
	return gulp.src('app/img/**/*')
	.pipe(cache(imagemin({
		interlaced: true,
		progressive: true,
		svgoPlugins: [{removeViewBox: false}],
		une: [pngquant()]
	})))
	.pipe(gulp.dest('dist/img'));
})

gulp.task('watch', ['browser-sync', 'sass'], function() {
	gulp.watch(['app/sass/**/*.sass', 'app/sass/**/*.scss'], ['sass']);
	gulp.watch('app/*html', browserSync.reload);
});

gulp.task('default', ['watch']);

gulp.task('build', ['clean', 'img', 'sass'], function() {
	var buildCss = gulp.src('app/css/**/*')
	.pipe(gulp.dest('dist/css'));

	var buildFonts = gulp.src('app/fonts/**/*')
	.pipe(gulp.dest('dist/fonts'));

	var buildJs = gulp.src('app/js/**/*')
	.pipe(gulp.dest('dist/js'));

	var buildHtml = gulp.src('app/*.html')
	.pipe(gulp.dest('dist'));
});