lib/patchit.js
function(next) {
        var source = config.getSource(asset.source);

        async.parallel([
          getFromSource.bind(null, source, asset, fromVersion, config),
          getFromSource.bind(null, source, asset, toVersion, config)
        ], next);
      }
function(next) {
        var source = config.getSource(asset.source);

        async.parallel([
          getFromSource.bind(null, source, asset, fromVersion, config),
          getFromSource.bind(null, source, asset, toVersion, config)
        ], next);
      }
function ( next ) { var source = config . getSource ( asset . source ) ; async . parallel ( [ getFromSource . bind ( null , source , asset , fromVersion , config ) , getFromSource . bind ( null , source , asset , toVersion , config ) ] , next ) ; }
get the source files to compare
get the source files to compare