longer.js

/*
 * This is how we have to do it now.
 */
var buffers = [];
var nread = 0;

something.on('data', function(chunk) {
  buffers.push(chunk);
  nread += chunk.length;
});
something.on('end', function() {
  var buffer;
  switch(buffers.length) {
    case 0: buffer = new Buffer(0); break;
    case 1: buffer = buffers[0]; break;
    default:
      buffer = new Buffer(nread);
      var n = 0;
      buffers.forEach(function(b) {
        var l = b.length;
        b.copy(buffer, n, 0, l);
        n += l;
      });
      break;
    }
    console.log(buffer.toString());
});

shorter.js

/*
 * Would it make sense to implement something like this?
 * Maybe a new class "BufferStream" instead of stacking
 * on top of Buffer.
 */
var buffer = new Buffer();

something.on('data', buffer.onData);
something.on('end', function(){
  buffer = buffer.end();
  console.log(buffer.toString());
});