Create a Bangle.isWorn() method

Another idea: just look at the accelerometer with a timeout?

(function(){
        let timeout;
        function setWorn(worn) {
             worn = !!worn; // undefined -> false
             if (timeout) clearTimeout(timeout);
             if (Bangle.isWorn === worn) return; // no change
             Bangle.isWorn = worn;
             Bangle.emit('worn', worn);
        }
        Bangle.on('accel', xyz => {
            if (Bangle.isCharging()) {
                setWorn(false);
           }
            else if (xyz.diff) {  // or Math.abs(xyz.diff) > 0.01?
                 setWorn(true);
                 // no movement for 1 minute
                 timeout = setTimeout(setWorn, 60000);
            }
        });
        Bangle.on('charging', charging => {
            // assume charging ends = watch picked up
            setWorn(!charging);
        });
})()

But I guess constantly running code for accell events might not be great for battery life :-(