How to use HRM-env event?

I've been doing some quick tests on my Bangle running 2v19. However, I'm not sure what the output of this event is supposed to mean. All I get when I run this is zeros. Is this expected functionality?

Bangle.setHRMPower(1);
Bangle.setOptions({hrmPushEnv:true});
Bangle.on('HRM-env', function(env) {
    console.log(env);
});

On mine, if the watch is on its back I see it reporting 1 when there's nothing there (eg the green LED ends up being off) and 0 when I get my hand close to the sensor. If I shine a torch at it or point it towards the window, the value rises.

The real use it for something like the flash counter though: https://banglejs.com/apps/?id=flashcount

For that you have to manually configure the sensor to run faster and to turn off the green LED:

Bangle.setOptions({hrmPollInterval:5});
Bangle.setHRMPower(1);
Bangle.setOptions({hrmGreenAdjust:false, hrmWearDetect:false, hrmPushEnv:true});
Bangle.hrmWr(0x10, 197&0xF8 | 4); // just SLOT2
Bangle.hrmWr(0x16, 0); // force env to be used as fast as possible
Bangle.on('HRM-env', function(env) {
    console.log(env);
});

So then it'll run nice and fast (200Hz in that case) and you could use it for some kind of sensing or communication

I'm trying to implement some type of wear detection by pulling the environment data. Maybe I'm misunderstanding how the watch does it. Do I have to rely on the other sensor to detect if something is close to the watch? I cannot replicate getting a one. Only zeros when I run the code above. I can get numbers above zero by shining my phone's flashlight, but this isn't useful for my use case.
I've been looking at this code snippet from the source code. https://github.com/espruino/Espruino/blob/master/libs/misc/hrm_vc31.c#L376

Ahh, ok - then actually all you need is:

Bangle.on("HRM-raw", h => {
  print(h.isWearing);
})
Bangle.setHRMPower(1)

The isWearing value is reported in HRM-raw