awful browserify transform to pack in client config.

pack.js

function packConfiguration() {
  var config = require('../../client-config.js');
  var clientConfig = 'module.exports=exports=(' + JSON.stringify(config) + ');\n';
  var clientTransformFile = require.resolve('../../../../public/media/js/config.js');

  return function clientConfigTransform(file) {
    if(file !== clientTransformFile) return through();
    var data = '';
    return through(
      function(inp) { data += inp; },
      function() {
        this.queue(clientConfig + data);
        this.queue(null);
      });
  }
}