Is it not using inheritance?

Actually it turns out it's a simple thing to add - I had to rush out a 1v69 release because of a serious regression, so I stuck it in.

var ow = new OneWire(A1);
var sensor = require("DS18B20").connect(ow);
sensor.setAlarm(20,30)
// then: sensor.searchAlarm() will return a list of sensor addresses that have the alarm set