webpack.bootstrap.config.js

const fs = require('fs');

function getBootstraprcCustomLocation() {
  return process.env.BOOTSTRAPRC_LOCATION;
}

const bootstraprcCustomLocation = getBootstraprcCustomLocation();

let defaultBootstraprcFileExists;

try {
  fs.statSync('./.bootstraprc');
  defaultBootstraprcFileExists = true;
} catch (e) {
  defaultBootstraprcFileExists = false;
}

if (!bootstraprcCustomLocation && !defaultBootstraprcFileExists) {
  /* eslint no-console: 0 */
  console.log('You did not specify a \'bootstraprc-location\' ' +
    'arg or a ./.boostraprc file in the root.');
  console.log('Using the bootstrap-loader default configuration.');
}

// DEV and PROD have slightly different configurations
let bootstrapDevEntryPoint;
if (bootstraprcCustomLocation) {
  bootstrapDevEntryPoint = 'bootstrap-loader/lib/bootstrap.loader?' +
    `configFilePath=${__dirname}/${bootstraprcCustomLocation}` +
    '!bootstrap-loader/no-op.js';
} else {
  bootstrapDevEntryPoint = 'bootstrap-loader';
}

let bootstrapProdEntryPoint;
if (bootstraprcCustomLocation) {
  bootstrapProdEntryPoint = 'bootstrap-loader/lib/bootstrap.loader?extractStyles' +
    `&configFilePath=${__dirname}/${bootstraprcCustomLocation}` +
    '!bootstrap-loader/no-op.js';
} else {
  bootstrapProdEntryPoint = 'bootstrap-loader/extractStyles';
}

module.exports = {
  dev: bootstrapDevEntryPoint,
  prod: bootstrapProdEntryPoint,
};