递归多叉树遍历

let rootNode = listArray.filter(la => {
                        return !la.parentId
                    }).sort((a, b) => {
                        return a.timestamp - b.timestamp
                    })
                    let array = [];

                    function getNode(node, level, arr) {
                        node.level = level;
                        arr.push(node);
                        let ccnode = listArray.filter(la => {
                            return la.parentId == node.id;
                        })
                        level++;
                        if (ccnode) {
                            ccnode.sort((a, b) => {
                                return a.timestamp - b.timestamp
                            }).forEach(cnode => {
                                debugger;
                                getNode(cnode,level, arr);
                            })
                        }
                    }
                    rootNode.forEach(rn => {
                        getNode(rn, 1, array);
                    })