Trying to find compass heading from magnetometer

Digging up an old thread here, but I kind of got it working enough for what I want.

I did what was suggested an took four readings at N,S,E,W, averaged them and deducted them from what Puck.mag() gave me back, then I ran it through the function I had before and it gave me accurate enough readings for the headings (0 for North, 180 for South, -90 for West and 90 for East). They aren't super accurate, but I'm guessing that's because of the nearby magnetic fields etc.

My code is below:

// Be sure to take your own readings for your own magnetic environment!
const avg = { "x": -967, "y": 514, "z": 1762 };

Puck.magOn();

Puck.on('mag', function(xyz){
  
  xyz.x -= avg.x;
  xyz.y -= avg.y;
  xyz.z -= avg.z;

  console.log((Math.atan2(xyz.y, xyz.x) * 180) / Math.PI);
});