const fs = require('fs');
const path = require('path');
const extractValues = require('modules-values-extract');
// get all *.css files in current directory:
const cssFiles = fs.readdirSync(__dirname)
  .filter((file) => file.match(/\.css/i))
  .map((file) => path.resolve(__dirname, file));
let config;
let myVariables;
module.exports = extractValues({
 files: cssFiles,
 /* optional list of plugin functions to use in processing, for example: */
 /* eslint-disable global-require */
 plugins: [require('postcss-calc'), require('precss')],
 /* eslint-enable global-require */
}).then((variables) => {
  myVariables = variables;
  return config;
});
config = {
  // ... various webpack config
  postcss: () => {
    return [
      /* eslint-disable global-require */
      require('postcss-cssnext')({
        features: {
          customProperties: {
            variables: myVariables,
          },
        },
      }),
      require('postcss-modules-values'),
      /* eslint-enable global-require */
    ];
  },
};