preprocessors/togeojson-gpx.preprocessor.js
function createIndices(callback) {
      const q = queue();
      geojson_files.forEach((gj) => {
        q.defer(createIndex, gj);
      });

      q.awaitAll((err) => {
        if (err) return callback(err);
        return callback();
      });
    }
function createIndices(callback) {
      const q = queue();
      geojson_files.forEach((gj) => {
        q.defer(createIndex, gj);
      });

      q.awaitAll((err) => {
        if (err) return callback(err);
        return callback();
      });
    }
function createIndices ( callback ) { const q = queue ( ) ; geojson_files . forEach ( ( gj ) => { q . defer ( createIndex , gj ) ; } ) ; q . awaitAll ( ( err ) => { if ( err ) return callback ( err ) ; return callback ( ) ; } ) ; }
create mapnik index for each geojson layer
create mapnik index for each geojson layer