Slick nav customization

Hello,
I am trying to customize slick-nav on mobile devices. I would like to change menu label after clicking menu. I’ve found in functions.php entry slicknav_menu_home, and changed it for custom initial value but I would like to change it also after clicking the button. I was trying to figure out how to do this by inspecting jquery.slicknav.js but can’t accomplish it. I did it by inspecting elements via console by follwing command:
document.querySelector(".slicknav_menutxt").childNodes[0].data = "Close menu";

If anyone could help me with this problem, it would be awesome!

Great day for everyone!
Kuba

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