code: function hookInstanbul(opts) {
    return loadJspmConfig(opts).then(loader => {
      sh.echo('Registering instrumentation hook to loader...');
      systemIstanbul.hookSystemJS(loader, opts.exclude(loader.baseURL));
  
      return loader;
    });
  }
docs: Resolve with a module loader which will add coverage instrumentation
  to src code.
  
  @param  {{exclude: function, config: function}}  opts coverage options
  @return {Promise<void, Error>}
  , config: {}