postcss-preset-env transform for sheetify. Use tomorrow's CSS syntax, today.
$ npm install sheetify-cssnextconst sheetify = require('sheetify/stream') const path = require('path') const opts = { transform: [ [ 'sheetify-cssnext', { sourcemap: false } ] ], basedir: __dirname } sheetify(path.join(__dirname, 'index.css'), opts) .pipe(process.stdout)