preprocessors/spatial-index.preprocessor.js
function copy(finished) {
    fs.createReadStream(infile)
      .once('error', callback)
      .pipe(fs.createWriteStream(outfile))
      .once('error', callback)
      .on('finish', finished);
  }
function copy(finished) {
    fs.createReadStream(infile)
      .once('error', callback)
      .pipe(fs.createWriteStream(outfile))
      .once('error', callback)
      .on('finish', finished);
  }
function copy ( finished ) { fs . createReadStream ( infile ) . once ( 'error' , callback ) . pipe ( fs . createWriteStream ( outfile ) ) . once ( 'error' , callback ) . on ( 'finish' , finished ) ; }
Create copy of original file into new dir
Create copy of original file into new dir