Persist expanded groups after read

function getExpandedGroups() {
    expandedGroups = [];
    try {
        let groupRows = $(".k-grouping-row");
        for (let i = 0; i < groupRows.length; i++) {
            let e = groupRows[i];
            let expanded = e.children[0]["ariaExpanded"];
            if (expanded === "true") {
                let groupName = $(e).find(".k-reset").text();
                let slicePos = groupName.lastIndexOf(" (");
                groupName = groupName.slice(0, slicePos);
                expandedGroups.push(groupName);
            }
        }
    }
    catch { }
    return expandedGroups;
}

function restoreExpandedGroups() {
    try {
        groupRows = $(".k-grouping-row");
        for (let i = 0; i < groupRows.length; i++) {
            let e = groupRows[i];
            let groupName = $(e).find(".k-reset").text();
            let slicePos = groupName.lastIndexOf(" (");
            groupName = groupName.slice(0, slicePos);
            if (expandedGroups.includes(groupName)) {
                attachmentTable.expandGroup(e);
            }
        }
    }
    catch { }
}

    let expandedGroups = getExpandedGroups();
    attachmentTable.dataSource.read().then(function () {    
        restoreExpandedGroups(expandedGroups);
    });