Batch converting layers on insets...So close, but need help!

Hi @suep89793525, the script you linked by CrazyPanda is great, and I probably could have adjusted it to run the way you want, but it wasn't structured ideally for that, and anyway I always like to learn, so I have written my own version. Please give it a try. Hasn't been tested much, so please let me know here if you find a bug and I will fix. It should work with placed .ai, .pdf, and .indd files.

- Mark

/**
 * Sets layer visibility of all placed items in active document.
 * All layers are set to invisible, unless the layer name exists
 * in `settings.visibleLayerNames`
 * NOTES:
 * - Adjust the settings object if you want to pre-populate
 *   the layerNames and visibleLayer.
 * - Do not specify `layerNames` in settings if you want
 *   to choose from *every* layer in every placed item.
 * @author m1b
 * @discussion https://community.adobe.com/t5/indesign-discussions/batch-converting-layers-on-insets-so-close-but-need-help/m-p/13885184
 */

var settings = {
    // layerNames: ['EN', 'ES', 'FR'], // uncomment this to limit the choices
    visibleLayerNames: ['FR'],
    showUI: true,
};

function main() {

    var doc = app.activeDocument,
        items = getLinkedPdfs(doc),
        identifiers = [];

    if (items.length == 0) {
        alert("No suitable linked files in document.");
        return;
    }

    // keep a stringified identifier
    // to bypass a bug with indesign
    // that assigns a new id every
    // time layer visibility is updated
    for (var i = 0; i < items.length; i++)
        identifiers.push(stringify(items[i]));

    // if no layer names specified
    // in settings, collect them all
    settings.layerNames = settings.layerNames || getLayerNames(items);
    settings.visibleLayerNames = settings.visibleLayerNames || [];

    // show UI
    if (
        settings.showUI
        && chooseLayers(settings) == false
    )
        // user cancelled UI
        return;

    // set each layer's visibility
    for (var i = items.length - 1; i >= 0; i--) {

        if (!items[i].isValid)
            continue;

        var len = items[i].graphicLayerOptions.graphicLayers.length;
        items[i].graphicLayerOptions.updateLinkOption = UpdateLinkOptions.KEEP_OVERRIDES;

        for (var j = 0; j < len; j++) {

            // get the item each time (because of bug mentioned earlier)
            var item = itemByStringifier(getLinkedPdfs(doc), identifiers[i], stringify);

            if (item.isValid)
                item.graphicLayerOptions.graphicLayers[j].currentVisibility = indexOf(item.graphicLayerOptions.graphicLayers[j].name, settings.visibleLayerNames) !== -1;

        }
    }

};

app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Set Layer Visibility');


/**
 * Returns array of linked pdf files.
 * @author m1b
 * @version 2023-06-24
 * @param {Document} doc - an Indesign Document.
 * @returns {Array<PageItem>}
 */
function getLinkedPdfs(doc) {

    var items = doc.links.everyItem().parent,
        linkedPdfs = [];

    for (var i = 0; i < items.length; i++)
        if (
            items[i].hasOwnProperty('pdfAttributes')
            && items[i].hasOwnProperty('graphicLayerOptions')
            && items[i].itemLink.status === LinkStatus.NORMAL
        )
            linkedPdfs.push(items[i]);

    return linkedPdfs;

};


/**
 * Gets a single item from array `items` based
 * on the result of a stringifier function.
 * @author m1b
 * @version 2023-06-23
 * @param {Array<PageItem>} items - an array of items from which to choose.
 * @param {String} identifier - the string to search for.
 * @param {Function} stringifier - a stringifying function.
 * @returns {PageItem}
 */
function itemByStringifier(items, identifier, stringifier) {

    for (var i = 0; i < items.length; i++)
        if (stringifier(items[i]) === identifier)
            return items[i];

};


/**
 * Generate a string just for the purpose
 * of identifying a particular linked item.
 * @author m1b
 * @version 2023-06-23
 * @param {PageItem} item - an Indesign placed item.
 * @returns {String}
 */
function stringify(item) {

    var str = '',
        delim = '|'

    if (
        item.itemLink
        && item.itemLink.filePath
    )
        str += item.itemLink.filePath + delim;

    if (item.graphicLayerOptions.graphicLayers.length > 0)
        str += item.graphicLayerOptions.graphicLayers.everyItem().name.join(delim) + delim;

    if (item.parentPage)
        str += item.parentPage.name + delim;

    return str;

};


/**
 * Returns index of obj in arr.
 * Returns -1 if not found.
 * @param {any} obj
 * @param {Array} arr
 * @returns {Number}
 */
function indexOf(obj, arr) {
    for (var i = 0; i < arr.length; i++)
        if (arr[i] === obj)
            return i;
    return -1;
};


/**
 * Collects array of layer names from linked pdf items.
 * @param {Array<PageItem>} items - the linked pdfs.
 * @returns {Array<String>}
 */
function getLayerNames(items) {

    var layerNames = [],
        already = {};

    for (var i = 0; i < items.length; i++)
        for (var j = 0; j < items[i].graphicLayerOptions.graphicLayers.length; j++)
            if (!already[items[i].graphicLayerOptions.graphicLayers[j].name]) {
                layerNames.push(items[i].graphicLayerOptions.graphicLayers[j].name);
                already[items[i].graphicLayerOptions.graphicLayers[j].name] = true;
            }

    return layerNames;

};


/**
 * Shows UI for selecting layers of document.
 * @author m1b
 * @version 2023-06-09
 * @param {Object} settings
 * @param {Document} settings.doc - an Indesign Document.
 */
function chooseLayers(settings) {

    var layerNames = settings.layerNames,
        selectedLayerNames = [],
        w = new Window("dialog { text:'Set Layer Visibility' }"),
        layersListBox = w.add("ListBox {alignment:['fill','fill'], properties:{multiselect:true, showHeaders:true, numberOfColumns:1, columnTitles:['Layer'] } }"),
        buttons = w.add("Group { orientation: 'row', alignment: ['right','bottom'], margins:[0,12,0,22] }"),
        cancelButton = buttons.add("Button { text:'Cancel', properties: { name:'cancel' } }"),
        okButton = buttons.add("Button { text:'Set Visibility', properties: { name:'ok' } }");

    // populate layers menu
    for (var i = 0; i < layerNames.length; i++)
        layersListBox.add('item', layerNames[i]);

    /**
     * Updates `selectedLayerNames`
     * when listbox selection changes.
     */
    layersListBox.onChange = function () {

        var sel = this.selection;
        selectedLayerNames = [];
        settings.layers = [];

        if (sel == null)
            return;

        for (var i = 0; i < sel.length; i++)
            selectedLayerNames.push(sel[i].text);

    };

    // set the initial selection
    var sel = [];
    for (var i = 0; i < settings.visibleLayerNames.length; i++) {
        var index = indexOf(settings.visibleLayerNames[i], settings.layerNames);
        if (index != -1)
            sel.push(index);
    }
    layersListBox.selection = sel;
    layersListBox.maximumSize.height = w.maximumSize.height - 200;;
    layersListBox.active = true;

    if (w.show() == 2)
        // user cancelled
        return false;

    // add the selected layers to settings object
    settings.visibleLayerNames = selectedLayerNames;

};

Edit 2023-06-24: added some error checking.