Trouble connecting puck.js to webpage

Hi - the issue is you've got two places where you can execute JavaScript - in the Web Browser, and in Puck.js itself. You're running code that's meant for Puck.js in the web browser.

The usage of the Puck name for Puck.write and Puck.eval is a bit confusing, but basically Puck.write/eval go in the Web Browser. Puck.mag/etc (or anything on http://www.espruino.com/Reference#Puck) runs in Puck.js.

If you want to get this working, use the two-way communication example from https://www.espruino.com/Web%20Bluetooth#two-way-communications

Then replace:

connection.write("setInterval(function(){Bluetooth.println(Puck.light());},100);NRF.on('disconnect', function() {reset()});\n",
              function() { console.log("Ready..."); });
          }, 1500);

with:

connection.write(`
        var zero = Puck.mag();
        var rep = 0;
        
        function onMag(p) {
            p.x -= zero.x;
            p.y -= zero.y;
            p.z -= zero.z;
            var s = Math.sqrt(p.x * p.x + p.y * p.y + p.z * p.z);
            if (!Boolean(s < 1000)) {
                digitalPulse(LED2, 1, 1000);
                rep++;
                Bluetooth.println(rep);
            }
        }
        Puck.on('mag', onMag);
        Puck.magOn();`,
              function() { console.log("Ready..."); });
          }, 1500);

... and you probably want to change the onLine handler to do something else with the data.

What's then happening is you're using .write to send the program (as a string) to Puck.js for execution, rather that running it on the PC