xrandr: How to check if mirroring screens

What's a clean way to check if my monitors are being mirrored or not with xrandr?

Background
I'm using polybar and as of now I have a script that launches an extra polybar if my second monitor is connected. Problem is that when I'm mirroring I don't want to launch that second bar. Here's my code if somebody's curious:

#!/bin/bash

# Terminate already running bar instances
killall -q polybar

# Wait until the processes have been shut down
while pgrep -u $UID -x polybar >/dev/null; do sleep 1; done

# Launch bar 
polybar main_bar -r & 

my_laptop_external_monitor=$(xrandr --query | grep 'HDMI-1')
if [[ $my_laptop_external_monitor = *connected* ]]; then
    polybar external_bar &
fi

I ran xrandr --listmonitors on my system, with and without cloned monitors:

Not cloned:

Monitors: 2
 0: +*DisplayPort-0 1920/598x1080/336+1920+0  DisplayPort-0
 1: +HDMI-0 1920/598x1080/336+0+0  HDMI-0

Cloned

Monitors: 2
 0: +*DisplayPort-0 1920/598x1080/336+0+0  DisplayPort-0
 1: +HDMI-0 1920/598x1080/336+0+0  HDMI-0

The only difference is the output's position within the screen, 1920+0 vs 0+0. When the monitor is mirrored, the position of both monitors are the same (both 0+0).

If you mirror your monitors this way ¹, a good way to check if a monitor is mirrored is to compare their positions in the ouput of xrandr --listmonitors.

I don't think there is a cleaner way than this. As far as I can tell, you don't actually mirror or clone monitors you only set their positions inside to screen in such a way that they overlap and when rendering, both monitors show the same picture because they're at the same location. That's why there isn't really a straightforward way to test for mirrored screens.

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¹Side Note: The monitor was cloned with the following command

xrandr --output HDMI-0 --same-as DisplayPort-0