Variables from different scripts are getting overridden

I am learning javascript and made a project where I have two canvases where I draw circles on. The scripts for each canvas is in its own file in the same folder. My problem is that for both of these scripts I am using the same variable names eg. radius and they seem to be shared between the two scripts.

I declare the variables as follows in the beginning of the file and then the function right afterwards.

const radius = 23;
const motionTrailLength = 30;
var context;
var xPos, yPos, maxX, maxY;
var dx = 2;
var dy = 2;

function init(canvas) {...}

I read that let and const “declared inside a { } block cannot be accessed from outside the block” so is there some way can wrap the script in those blocks to stop them from getting overridden?