started with recursive then want to cry :(

function mergeLists(head1, head2) {

const elem = []
const res = (node, node2) => {
    let elem = node2 ? (node.data > node2.data ? node2 :node): node
    let nElem = node2 ? (node.data <= node2.data ? node2 :node): null
    return {
        data: elem.data,
        next: elem.next ? res(elem.next, nElem): nElem? res(nElem, null):null
    }
};
return res(head1,head2)

}