Use Automator App Variables as imput for Javascript action steps

Question

I am trying to input the content of a variable generated with the Automator app onto the next action step, to define the value of a javascript script variable. Change the variable using javascript code and push the result further to the next action step. Then turn it back into an Automator variable, or update the one previously used as input. I am sure you will find it as a simple thing, but I couldn't find a way to get it working. This question might be silly, after all. Many thanks in advance. Check the screenshot of the Automator sequence of steps. Screenshot of the actions set in Automator App

function run(input) {
    
    var str = input;
var l1 = str.replace(/ /g, "_");
    str = l1;
var l2 = str.replace(/:/g, "-");

    return l2;
}