PostCSS-Reference Node API example

import-bs.js

// dependencies
var fs = require("fs");
var postcss = require("postcss");
var atImport = require("postcss-import");
var nested = require("postcss-nested");
var reference = require("postcss-reference");

var file = "style.css";

// css to be processed
var css = fs.readFileSync("./" + file, "utf8");

// process css
postcss()
  .use(atImport())
  .use(nested())
  .use(reference())
  .process(css, {
      from: "./" + file,
      to: file
  }).then(function (result) {
      fs.writeFileSync(file, result.css);
      if ( result.map ) fs.writeFileSync(file + '.map', result.map);
  });

package.json

{
  "name": "postcss-reference-bug-testing",
  "version": "1.0.0",
  "description": "Fixing ze bugs",
  "main": "gulpfile.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "autoprefixer-core": "^6.0.1",
    "bootstrap": "^3.3.6",
    "css-mqpacker": "^4.0.0",
    "gulp": "^3.9.1",
    "gulp-postcss": "^6.1.0",
    "postcss-import": "^8.0.2",
    "postcss-mixins": "^4.0.0",
    "postcss-nested": "^1.0.0",
    "postcss-reference": "^1.0.3",
    "postcss-simple-vars": "^1.2.0"
  }
}

style.css

@reference {
    @import "node_modules/bootstrap/dist/css/bootstrap.css";
}
.button {
    @references .btn, .btn-default;
}