How find strokes with different thicknesses

There you go. Save as "fixHairlines.jsx" in your own personal Scripts folder (if this sounds daunting, read https://indesignsecrets.com/how-to-install-a-script-in-indesign-that-you-found-in-a-forum-or-blog-post.php ), double-click to run. It presents a simple dialog in which you can fill in the minimum and maximum weights to change (both inclusive) and the weight to change to.

Did only a very small test but I foresee no problems. InDesign pops up an automatic message if you try to find objects on locked layers or in locked stories, and to prevent that, I disable these two options. The other settings – type, master pages, hidden layers – should (theoretically) remain as last set.

It does not seem to work with finding 0 point line weights, but I guess that should be a rarity – this script is to change existing line weights, not to add one to objects that don't have one.

It's undo-able in a single step.

//Find and change line weights between certain values
// A Jongware Script 05-Jun-2019
app.doScript(fixHairlines, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, "Fix hairlines");
function fixHairlines()
{
    var thicknessDialog = app.dialogs.add({name:"Fix hairlines", canCancel:true});
    with (thicknessDialog)
    {
        with(dialogColumns.add())
        {
            with(dialogRows.add())
            {
                staticTexts.add({staticLabel:"Minimum weight"});
                minweight = measurementEditboxes.add({editUnits:MeasurementUnits.POINTS, editValue:0.01,largeNudge:0.1,smallNudge:0.01,minimumValue:0,maximumValue:999});
            }
            with(dialogRows.add())
            {
                staticTexts.add({staticLabel:"Maximum weight"});
                maxweight = measurementEditboxes.add({editUnits:MeasurementUnits.POINTS, editValue:1.0,largeNudge:0.1,smallNudge:0.01,minimumValue:0,maximumValue:999});
            }
            with(dialogRows.add())
            {
                staticTexts.add({staticLabel:"Change to"});
                setweight = measurementEditboxes.add({editUnits:MeasurementUnits.POINTS, editValue:1.0,largeNudge:0.1,smallNudge:0.01,minimumValue:0,maximumValue:999});
            }
        }
    }
    if (thicknessDialog.show() == true)
    {
        app.findObjectPreferences = null;
        app.findChangeObjectOptions.includeLockedLayersForFind = false;
        app.findChangeObjectOptions.includeLockedStoriesForFind = false;
        list = app.documents[0].findObject();
        for (i=0; i<list.length; i++)
        {
            if (list.strokeWeight >= minweight.editValue &&
                list.strokeWeight <= maxweight.editValue)
                list.strokeWeight = setweight.editValue;
        }
    }
}