Node stream adventure code

Stream adventure

/*
Part 1 Stream adventure
*/
console.log("beep boop");

/*
Part 2 Meet Pipe
*/
var fs = require('fs');
fs.createReadStream(process.argv[2]).pipe(process.stdout);

/*
Part 3 Input Output
*/
process.stdin.pipe(process.stdout);

/*
Part 4 Transform
*/

var through = require('through');
var tr = through(write);
process.stdin.pipe(tr).pipe(process.stdout);

    
function write (buf) { this.queue(buf.toString().toUpperCase());}

/*
Part 4 Lines upper and lower
*/

var through = require('through');
var split = require('split');
var tr = through(write);

var linenum = 0;

var write = function (buf){
    var strbuf = buf.toString();
    this.queue(linenum % 2 === 0
        ? strbuf.toLowerCase() + '\n'
        : strbuf.toUpperCase() + '\n'
    );
    linenum ++;
    
};
    
var tr = through(write);
process.stdin.pipe(split()).pipe(tr).pipe(process.stdout);

/*
Part 5 Concat and reverse
*/


/*
part 6 http server
*/
  var http = require('http');
    var through = require('through');
    
    var server = http.createServer(function (req, res) {
        if (req.method === 'POST') {
            req.pipe(through(function (buf) {
                this.queue(buf.toString().toUpperCase());
            })).pipe(res);
        }
        else res.end('send me a POST\n');
    });
    server.listen(parseInt(process.argv[2]));

/*
part 7
*/