DS18x20 no device

[mauroForlimpopoli]

Good morning,
I'm using a net with 2 sensors DS18B20 . Following your example:
...
try {
sensor = new DS18X20({
bus,
index: 1
});
trace('Found 2nd:', sensor.toString(), '\n');
} catch {
trace('No 2nd!\n');
}
I
...
it works fine, but if disconnect a sensor, I get this error:
C:\moddable\modules\drivers\onewire\DS18X20.js (49) # Break: throw!
How can I receive only an alert and not a "throw new Error("no device");" that crash the device ?
Regards