/**
 * Updates any *labelled* QRCode graphic with the page name.
 * @author m1b
 * @discussion https://community.adobe.com/t5/indesign-discussions/generating-qr-codes-in-indesign-using-current-page-number-is-it-possible/m-p/13749888
 */
function main() {

    var doc = app.activeDocument,
        label = 'PageNumberQRCode',
        counter = 0;

    for (var i = 0; i < doc.pages.length; i++) {

        var page = doc.pages[i],
            qrCodeFrame = getPageItemByLabel(page, label);

        if (
            qrCodeFrame != undefined
            && qrCodeFrame.isValid
        ) {
            qrCodeFrame.allGraphics[0].createPlainTextQRCode(page.name);
            counter++;
        }

    }

    alert('Updated ' + counter + ' QR Codes.');

};

app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Update QR-Codes');


/**
 * Returns page item on page by matching label.
 * @param {Page} page
 * @param {String} label
 * @param {PageItem}
 */
function getPageItemByLabel(page, label) {

    for (var i = 0; i < page.pageItems.length; i++)
        if (page.pageItems[i].label === label)
            return page.pageItems[i];

};