generator-markup-source/app/templates/_dev/gulpfile.js

This is generator using yeoman for markup source

const gulp = require('gulp');
const sass = require('gulp-sass');
const browserSync = require('browser-sync').create();
const useref = require('gulp-useref');
const uglify = require('gulp-uglify');
const gulpIf = require('gulp-if');
const imagemin = require('gulp-imagemin');
const cache = require('gulp-cache');
const del = require('del');
const runSequence = require('run-sequence');
const autoprefixer = require('autoprefixer');
const cssnano = require('cssnano');
const changed = require('gulp-changed');
const postcss = require('gulp-postcss');
const uncss = require('postcss-uncss');
const modernizr = require('gulp-modernizr');
const assemble = require('assemble');
const app = assemble();
const extname = require('gulp-extname');

// compile sass and minify css
gulp.task('css', ['sass'], function () {
  var plugins = [
    autoprefixer({browsers: ['last 1 version']}),
    cssnano()
  ];
  return gulp.src('../common/css/*.css')
  .pipe(postcss(plugins))
  .pipe(gulp.dest('../common/css'));
});
gulp.task('sass', () => {
  return gulp.src('_scss/style.scss')
  .pipe(changed('../common/css', {hasChanged : changed.compareContents}))
  .pipe(sass())
  .pipe(gulp.dest('../common/css/'))
  .pipe(browserSync.reload({
    stream : true
  }))
});

gulp.task('browserSync', function() {
  browserSync.init({
    server: {
      baseDir: '../',
    },
    startPath : '/mock'
  })
});
gulp.task('load', function(cb) {
  app.partials('_templates/_partials/*.hbs');
  app.layouts('_templates/_layouts/*.hbs');
  app.pages('_templates/_pages/*.hbs');
  app.data('_templates/_data/*.{json,yml}');
  app.option('layout', 'default');
  cb();
});
gulp.task('assemble', ['load'], function() {
  return app.toStream('pages')
  .pipe(app.renderFile())
  .pipe(extname())
  .pipe(app.dest('../mock'));
});
gulp.task('useref', ['assemble'], function(){
  return gulp.src('../mock/**/*.html')
  .pipe(useref())
  .pipe(gulpIf('*.js', uglify()))
  .pipe(gulp.dest('../mock'))
});

gulp.task('images', function(){
  return gulp.src('../common/images/**/*.+(png|jpg|gif|svg)')
  .pipe(cache(imagemin({
    interlaced: true
  })))
  .pipe(gulp.dest('../common/images'))
});
gulp.task('clean:dist', function() {
  return del.sync('../mock/');
});

gulp.task('modernizr', function() {
  return gulp.src('../common/js/*.js')
  .pipe(modernizr('../common/js/modernizr-custom.js'));
});

gulp.task('watch', function (){
  gulp.watch('_scss/**/*.scss', ['sass']);
  gulp.watch('_templates/**/*.+(hbs|json)', ['assemble']);
  gulp.watch('../mock/**/*.html').on('change', browserSync.reload);
  gulp.watch('../common/css/*.css').on('change', browserSync.reload);
  gulp.watch('../common/js/**/*.js').on('change', browserSync.reload);
});

gulp.task('dev', function (callback) {
  runSequence('watch',
      ['sass', 'assemble', 'browserSync'],
      callback
  )
});
gulp.task('prod', function(){
  return runSequence ('useref', ['css']);
});