code: function loadFile(entry, opts, formatter, cb, errCb) {
        var type = entry.assetType || entry.bundle;
        formatter = formatter || ss.client.formatters[entry.ext || type];
        if (!formatter) {
          throw new Error('Unsupported file extension \'.' + entry.ext + '\' when we were expecting some type of ' +
            ((type||'unknown').toUpperCase()) + ' file. Please provide a formatter for ' + (entry.file) + ' or move it to /client/static');
        }
        if (formatter.assetType !== type) {
          throw new Error('Unable to render \'' + entry.file + '\' as this appears to be a ' + (type.toUpperCase()) +
            ' file. Expecting some type of ' + (type.toUpperCase()) + ' file in ' + (path.dirname(entry.file)) + ' instead');
        }
  
        // Use the formatter to pre-process the asset before bundling
        try {
          return formatter.call(this.clientFilePath(entry.file), opts, cb, errCb);
        } catch (err) {
          return errCb(err);
        }
      }
docs: API for implementing bundlers