Reassign variable in numerous modules?

I have a variable let activeNode; in main.js. It can be changed by either keyboard input or mouse input. The functions dealing with each are modularized into their own files keyboard.js and mouse.js. activeNode is exported into these modules.

Whenever the functions attempt to reassign the imported variable activeNode, console logs the error Uncaught TypeError: Assignment to constant variable.

I've seen other answers saying to also create and export a function updateVariable(var) in main.js and then call it in the modules to reassign activeNode, but I'd prefer not having to create an export and entire function just to reassign a variable.

Is there any other way to accomplish cross-module reassignment of variables? (And without having to pass the variable into the module function calls, because the mouse input function calls are deeply nested in main.js and I don't want to have to tunnel a parameter through a bunch of higher level functions.)