Create gradient map from swatches

I accidentally found a way to get color from color swatches.

But I do not think that this will help in this incomprehensible task.

Do not press Ctrl-key before and during the execution of the script.

var c1 = app.foregroundColor;
for (var i = 1;;i++)
    {
    var d = new ActionDescriptor();
    var r = new ActionReference();
    r.putIndex(stringIDToTypeID("colors"), i);
    d.putReference(stringIDToTypeID("null"), r);
    try { executeAction(stringIDToTypeID("select"), d, DialogModes.NO); } catch(e) { break; }
    var c = app.foregroundColor;
    app.foregroundColor = c1;
    alert("Swatch " + i+ "\n\n#" + c.rgb.hexValue);
    }
    
alert(i + " Done!")

If I can choose and better.

from two, three, four, five … swatches - or from all swatches?

Can you show/give an example file?