Содержимое файла gulpfile.js

Содержимое файла gulpfile.js для рабочей папки app с билдом в папку dist:

var gulp         = require('gulp'),
    sass         = require('gulp-sass'),
    browserSync  = require('browser-sync'),
    concat       = require('gulp-concat'),
    uglify       = require('gulp-uglifyjs'),
    cssnano      = require('gulp-cssnano'),
    rename       = require('gulp-rename'),
    del          = require('del'),
    imagemin     = require('gulp-imagemin'),
    pngquant     = require('imagemin-pngquant'),
    cache        = require('gulp-cache'),
    autoprefixer = require('gulp-autoprefixer');


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


gulp.task('scripts', function() {
  return gulp.src([
    'app/libs/jquery/dist/jquery.min.js',
    'app/libs/magnific-popup/dist/jquery.magnific-popup.min.js'
  ])
  .pipe(concat('libs.min.js'))
  .pipe(uglify())
  .pipe(gulp.dest('app/js'));
});


gulp.task('css-libs', ['sass'], function() {
  return gulp.src('app/css/libs.css')
  .pipe(cssnano())
  .pipe(rename({suffix: '.min'}))
  .pipe(gulp.dest('app/css'));
})


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


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}],
    use: [pngquant()]
  })))
  .pipe(gulp.dest('dist/img'));
});


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


gulp.task('build', ['clean', 'img', 'sass', 'scripts'], function() {
  var buildCss = gulp.src([
      'app/css/main.css',
      'app/css/libs.min.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'));

});

Содержимое файла gulpfile.js для рабочей папки app без билда:

var gulp         = require('gulp'),
    sass         = require('gulp-sass'),
    autoprefixer = require('gulp-autoprefixer'),
    cleanCSS     = require('gulp-clean-css'),
    rename       = require('gulp-rename'),
    browserSync  = require('browser-sync').create(),
    concat       = require('gulp-concat'),
    uglify       = require('gulp-uglify');

gulp.task('browser-sync', ['styles', 'scripts'], function() {
    browserSync.init({
        server: {
            baseDir: "./app"
        },
        notify: false
    });
});

gulp.task('styles', function () {
  return gulp.src('sass/*.sass')
  .pipe(sass({
    includePaths: require('node-bourbon').includePaths
  }).on('error', sass.logError))
  .pipe(rename({suffix: '.min', prefix : ''}))
  .pipe(autoprefixer({browsers: ['last 15 versions'], cascade: false}))
  .pipe(cleanCSS())
  .pipe(gulp.dest('app/css'))
  .pipe(browserSync.stream());
});

gulp.task('scripts', function() {
  return gulp.src([
    './app/libs/modernizr/modernizr.js',
    './app/libs/jquery/jquery-1.11.2.min.js',
    './app/libs/waypoints/waypoints.min.js',
    './app/libs/animate/animate-css.js',
    ])
    .pipe(concat('libs.js'))
    // .pipe(uglify()) //Minify libs.js
    .pipe(gulp.dest('./app/js/'));
});

gulp.task('watch', function () {
  gulp.watch('sass/*.sass', ['styles']);
  gulp.watch('app/libs/**/*.js', ['scripts']);
  gulp.watch('app/js/*.js').on("change", browserSync.reload);
  gulp.watch('app/*.html').on('change', browserSync.reload);
});

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