Reading /dev/psaux stream with nodejs

gistfile1.js

var fs = require('fs');

var readStream = fs.ReadStream('/dev/psaux');

var mouseMovements = [];

readStream.on('data', function(packet) {
    var buf = packet.readInt8(0);
    var mouse = {
        leftBtn:    !!(buf & 1)
      , rightBtn:   !!(buf & 2)
      , middleBtn:  !!(buf & 4)
      , always:     !!(buf & 8)
      , xSign:      !!(buf & 16)
      , ySign:      !!(buf & 32)
      , xOver:      !!(buf & 64)
      , yOver:      !!(buf & 128)
      , xDelta:     packet.readInt8(1)
      , yDelta:     packet.readInt8(2)
    };

    console.log(mouse);
    
});


readStream.on('close', function() {
    console.log('Closed readstream');
});