css = () => {
  let src = [
    './src/css/**/{layui,*}.css'
  ];
  return gulp.src(src)
  .pipe(sourcemaps.init())
  .pipe(cleanCSS({
    compatibility: 'ie8'
  }))
  .pipe(concat('layui.css', {newLine: ''}))
  .pipe(sourcemaps.write('.'))
  .pipe(gulp.dest(dest +'/css'));
}
/{layui,layui.all,'+ config.modules +'}.js'
  ];
  return gulp.src(src)
  .pipe(sourcemaps.init())
  .pipe(uglify({
    output: {
      ascii_only: true // escape Unicode characters in strings and regexps
    },
    ie: true
  }))
  .pipe(concat('layui.js', {newLine: ''}))
  .pipe(header.apply(null, config.comment))
  .pipe(sourcemaps.write('.'))
  .pipe(gulp.dest(dest));
};

// css
const css = () => {
  let src = [
    './src/css/*