Saved search to Fetch the Tax Percentage From Purchase order

/**
 * @description search function to fetch the tax percent from the purchase order record
 * @param {number} poRecordsId - purchase order internal id
 * @return itemObj - object containing tax percentage
 */
function purchaseOrderDetails(poRecordsId) {
    try {
        let purchaseorderSearchObj = search.create({
            type: "purchaseorder",
            filters:
                [
                    ["type", "anyof", "PurchOrd"],
                    "AND",
                    ["internalid", "anyof", poRecordsId],
                    "AND",
                    ["mainline", "is", "F"],
                    "AND",
                    ["cogs", "is", "F"],
                    "AND",
                    ["shipping", "is", "F"]
                ],
            columns:
                [
                    search.createColumn({name: "line", label: "Line ID"}),
                    search.createColumn({
                        name: "rate",
                        join: "taxItem",
                        label: "Rate"
                    })
                ]
        });
        let searchResultCount = purchaseorderSearchObj.runPaged().count;
        let itemObj = {}
        if (searchResultCount > 0) {

            purchaseorderSearchObj.run().each(function (result) {
                let memberLine = result.getValue({
                    name: "line",
                    label: "Line ID"
                })
                let memberTax = result.getValue({
                    name: "rate",
                    join: "taxItem",
                    label: "Rate"
                })

                itemObj[memberLine] = memberTax;
                return true
            });
            return itemObj;
        }

    } catch (e) {
        log.error("error @ search function", e)

    }
}