Puck.js with LDR - how to deal with light that is always on?

Actually yes, I guess you could remove the pullup if it's on for too long.

So maybe some additional code:

var onCount = 0;
var pulledUp = true;
setInterval(function() { // every 10 seconds
  if (!pulledUp) pinMode(D2,"input_pullup");
  if (D2.read()) { // LED is off - all ok
    onCount = 0;
    pulledUp = true;
  } else {
    onCount++;
    if (onCount>6) { // >60 secs on
      pulledUp = false;
    }
  }
  if (!pulledUp) pinMode(D2,"input");
}, 10000);

//And then in your setWatch
setWatch(function(e) {
  if (!pulledUp) return;
  //...