gulpfile.js

var gulp = require('gulp'),
  plumber = require('gulp-plumber'),
  rename = require('gulp-rename');
var autoprefixer = require('gulp-autoprefixer');
var concat = require('gulp-concat');
var uglify = require('gulp-uglify');
var imagemin = require('gulp-imagemin'),
  cache = require('gulp-cache');
var minifycss = require('gulp-minify-css');
var sass = require('gulp-sass');
var sourcemaps = require('gulp-sourcemaps');
var browserSync = require('browser-sync');

var project = '.';
var source = project + '/assets/';
var bower = project + '/bower_components/';

gulp.task('browser-sync', function() {
  browserSync({
    server: {
      baseDir: "./"
    }
  });
});

gulp.task('bs-reload', function() {
  browserSync.reload();
});

gulp.task('images', function() {
  gulp.src('src/images/**/*')
    .pipe(cache(imagemin({
      optimizationLevel: 3,
      progressive: true,
      interlaced: true
    })))
    .pipe(gulp.dest('dist/images/'));
});
gulp.task('js:combine', function() {
  var scripts = [
    bower + 'jquery/dist/jquery.min.js',
    bower + 'bxslider-4/dist/jquery.bxslider.min.js'

  ];
  return gulp.src(scripts)
    .pipe(sourcemaps.init())
    .pipe(concat('production.js'))
    .pipe(sourcemaps.write('../maps'))
    .pipe(gulp.dest('dist/js'));
});

gulp.task('styles', function() {
  gulp.src(['src/styles/**/*.scss'])
    .pipe(plumber({
      errorHandler: function(error) {
        console.log(error.message);
        this.emit('end');
      }
    }))
    .pipe(sass())
    .pipe(autoprefixer('last 2 versions'))
    .pipe(gulp.dest('dist/styles/'))
    .pipe(rename({
      suffix: '.min'
    }))
    .pipe(minifycss())
    .pipe(gulp.dest('dist/styles/'))
    .pipe(browserSync.reload({
      stream: true
    }))
});

gulp.task('scripts', function() {
  return gulp.src('src/scripts/**/*.js')
    .pipe(plumber({
      errorHandler: function(error) {
        console.log(error.message);
        this.emit('end');
      }
    }))
    .pipe(concat('main.js'))
    .pipe(gulp.dest('dist/scripts/'))
    .pipe(rename({
      suffix: '.min'
    }))
    .pipe(uglify())
    .pipe(gulp.dest('dist/scripts/'))
    .pipe(browserSync.reload({
      stream: true
    }))
});

gulp.task('default', ['browser-sync'], function() {
  gulp.watch("src/styles/**/*.scss", ['styles']);
  gulp.watch("src/scripts/**/*.js", ['scripts']);
  gulp.watch("*.html", ['bs-reload']);
  gulp
});