Working on data inside compressed archives using node.js and pipes

compress.js

var es = require('event-stream')

process.stdin
  .pipe(es.split())
  .pipe(es.map(function (data, callback) {
    var line = data.toString().split(',');
    if (line.length>3){
      var filename = line[0]; 
      var date = [line[1].substr(0,4), line[1].substr(4,2), line[1].substr(6)].join('-');
      date = + new Date(date);
      var bid = line[2];
      var offer = line[3];
      data = [date, bid, offer].join(',') + '\n'
    }
    callback(null, data);
  }))
 
  .pipe(process.stdout); 

//time unzip -p input.zip | node ../fix.js | gzip -cf > output.gz | tail -n1