Alternative to static property in a class?

Looks like static properties in classes are not supported?

    class Foo {
        static get CH0() { return 0xdeadbeef; }
        constructor() {
            print('nothing to see here')
        }
    }

In a browser Foo.CH0 returns 0xdeadbeef as expected.
In Espruino Foo.CH0 returns undefined. No error either, so it's parsed, but ignored / lost somewhere? It's not on the instance if you create a new instance of the class either.

Why I want to do this? I'm writing a driver for a dual DAC, and while playing around, I found it's sort of easy to mix up the voltage and channel. Like dac.setVoltage(0, 1), or dac.setVoltage(1, 0) sets channel one to zero volts? And since this DAC (GP8403) has a feature of setting both channels at the same time, the channel parameter has 3 valid values.
So I was thinking about some magic values as constants, that would be outside the allowed voltage range. something like dac.setVoltage(0, GP8403.CH1), and if GP8403.CH1 is outside of the 0..10V range, I can throw on invalid input, and any bug should be caught early. I know, might be overly defensive...

Non-static getter does work. So dac.setVoltage(0, dac.CH1) works just fine.

And of course I could define a constant, and export that as well from my module. But this approach doesn't feel really nice I guess. Or am I missing something?

So, what would you recommend? Am I overthinking this?