code: function transform (stream, target) {
    const filter = {
      scripts: $.filter((file) => /\.jsx?$/.test(file.path), { restore: true }),
      styles: $.filter((file) => /\.styl$/.test(file.path), { restore: true })
    }
  
    return stream
    .pipe($.plumber(::console.error))
  
    // scripts
    .pipe(filter.scripts)
      .pipe($.sourcemaps.init())
        // include inline styles
        .pipe($.replaceRelative(/require\('\.\/(.*?\.styl')\)/g, (file, match, callback) => {
          const includePath = match.match(/\('(.*?\.styl)'\)/)[1]
          readFile(path.resolve(path.dirname(file.path), includePath), (error, data) => {
            const css = stylus(data.toString()).render()
            postcss([
              autoprefixer({
                browsers: ['last 2 versions']
              }),
              cssnano
            ])
            .process(css)
            .then(function (result) {
              return callback(`"${result.css}"`)
            })
          })
        }))
        .pipe($.babel({/** see .babelrc **/}))
      .pipe($.sourcemaps.write())
    .pipe(filter.scripts.restore)
  
    // styles
    .pipe(filter.styles)
      .pipe($.stylus())
      .pipe($.postcss([
        autoprefixer({
          browsers: ['last 2 versions']
        })
      ]))
    .pipe(filter.styles.restore)
  
    .pipe($.plumber.stop())
    .pipe(gulp.dest(target))
  }
docs: Lazypipe alternative re-usable code
  @param  {[type]} stream [description]
  @param  {[type]} target [description]
  @return {[type]}        [description]