SCRIPTING AND COMPUTER CODING (JAVA SCRIPT) In Java Script and JS Processing, what would you write to create a toggle function (if G is pressed, it would either draw a shape on the canvas to it would remove it)

the reason i ask is bc im making a program for a customizable Tesla Cyber Truck that has other features like headlights, all of it is drawn as ellipses, squares, quads, basically 2D shapes, a lot of if and else statements as well, but the only way to change it is to change variables within the script, and im trying to link my program with a basic and universal keyboard layout