Pull files using streams and save a copy

archive-file.js

  var singleScan = function(file, callback) {
  
    var path      = file;
    var fileArray = file.split('/');
    
    var name = fileArray[fileArray.length - 1];
    var bead = fileArray[fileArray.length - 2];
    
    fs.stat('archive/' + bead + '_' + name, function(err, stats) {
      if(err) {
  
        // READ UP SOURCE FILE AND WRITE TO ARCHIVE DESTINATION
        var metricStream = fs.createReadStream(path, {
          flags: 'r',
          encoding: 'utf8',
          mode: 0666
        });

        var archiveStream = fs.createWriteStream('archive/' + bead + '_' + name, {
          flags: 'w',
          encoding: 'utf8',
          mode: 0775
        });

        // Open file and stream data out
        metricStream.on('open', function(fd) {

          metricStream.on('data', function(data) {
            archiveStream.write(data, 'utf8');
          });

          metricStream.on('error', function(err) { 
            console.log(err);
          });

          // When EOF, push new beadChip object to beadChips array
          metricStream.on('end', function() { 
            beadChips.push(new beadChip('archive/' + bead + '_' + name));
            callback();
          });
        });
      } else {
        beadChips.push(new beadChip('archive/' + bead + '_' + name));
        callback();
      }
    });
  };