os-timesync can help you check whether NTP time sync is enabled in OS settings. It can do so reliably on OS X and Windows and somewhat less reliably on Linux. Note that the result does not tell you whether the local time is accurate.

var timesync = require("os-timesync");

timesync.checkEnabled(function (err, enabled) {
    if (err) {
        console.log("can't check: " + err.toString());
        return;
    }
    console.log("enabled =", enabled);
});