Mass update script for image alt tags

Hello,

I am trying to implement a mass update script to only add image alt content on an item's associated image if there is no value.

/**

 * @NApiVersion 2.1

 * @NScriptType MassUpdateScript

 */

define(['N/record', 'N/log'], (record, log) => {


    const update = (context) => {

        try {

            // Load the Item Record

            const itemRec = record.load({

                type: context.type,

                id: context.id,

                isDynamic: true

            });


            // Get Store Display Name

            const storeDisplayName = itemRec.getValue({ fieldId: 'storedisplayname' }).replace(/[&<>'"\/,]/g, '') || '';



            const lineCount = itemRec.getLineCount({ sublistId: 'itemimages' });

            if (lineCount > 0) {

                for (let i = 0; i < lineCount; i++) {

                    const altTagCaption = itemRec.getSublistValue({

                        sublistId: 'itemimages',

                        fieldId: 'altTagCaption',

                        line: i

                    });


                    if (!altTagCaption) {

                        itemRec.setSublistValue({

                            sublistId: 'itemimages',