Sample Build for CSS in Node

css.js

var fs = require('fs');
var path = require('path');
var glob = require('glob');

var nodesass = require('node-sass');
var postcss = require('postcss');
var autoprefixer = require('autoprefixer')({ browsers: ['last 2 versions', 'ie >= 9'] });
var cssnano = require('cssnano');
var cssmodules = require('postcss-modules')({});

//Process SCSS Files
glob('src/css/**/*.scss', {}, function(err, files) {
    if(err) {
        console.log('Could not glob .SCSS files!', err);
        return;
    }

    files.filter(fn => !/^_/.test(path.basename(fn))).map(fn => {
        var out    = path.resolve('./public',  path.basename(fn).split('.').slice(0, -1).join('.')),
            outCSS = out +'.css',
            outMap = out +'.css.map';

        var Sass = nodesass.renderSync({
            file: path.resolve(fn),
            outFile: outCSS,
            sourceMap: true,
            outputStyle: 'expanded'
        });

        //Run PostCSS
        postcss([autoprefixer, cssnano]).process(Sass.css, {
            map: { prev: Sass.map.toString() }
        }).then(PostCSS => {
            fs.writeFileSync(outCSS, PostCSS.css);
            fs.writeFileSync(outMap, PostCSS.map);
        }, err => {
            console.log('PostCSS Error:', err);
        });
    });
});