以下代码的工作示例在jsFiddle上。

通过id对树进行索引，并从每个节点向上遍历树，然后计数直到您击中根为止。首先通过索引，我们可以达到O（n）时间复杂度（取决于树的密度）。*已更新以满足排序要求，并允许排除根节点：

function levelAndSort(data, startingLevel) {    // indexes    var indexed = {};        // the original values    var nodeIndex = {};      // tree nodes    var i;    for (i = 0; i < data.length; i++) {        var id = data[i].id;        var node = { id: id, level: startingLevel, children: [], sorted: false        };        indexed[id] = data[i];        nodeIndex[id] = node;    }    // populate tree    for (i = 0; i < data.length; i++) {        var node = nodeIndex[data[i].id];        var pNode = node;        var j;        var nextId = indexed[pNode.id].parentId;        for (j = 0; nextId in nodeIndex; j++) { pNode = nodeIndex[nextId]; if (j == 0) {     pNode.children.push(node.id); } node.level++; nextId = indexed[pNode.id].parentId;        }    }    // extract nodes and sort-by-level    var nodes = [];    for (var key in nodeIndex) {        nodes.push(nodeIndex[key]);    }    nodes.sort(function(a, b) {        return a.level - b.level;    });    // refine the sort: group-by-siblings    var retval = [];    for (i = 0; i < nodes.length; i++) {        var node = nodes[i];        var parentId = indexed[node.id].parentId;        if (parentId in indexed) { var pNode = nodeIndex[parentId]; var j; for (j = 0; j < pNode.children.length; j++) {     var child = nodeIndex[pNode.children[j]];     if (!child.sorted) {         indexed[child.id].level = child.level;         retval.push(indexed[child.id]);         child.sorted = true;     } }        }        else if (!node.sorted) { indexed[node.id].level = node.level; retval.push(indexed[node.id]); node.sorted = true;        }    }    return retval;}

例：

// level 0 (root) excludedvar startingLevel = 1;var someData = [    {id : "id-1", parentId : "id-0"},    {id : "id-2", parentId : "id-0"},    {id : "id-3", parentId : "id-2"},    {id : "id-4", parentId : "id-3"},    {id : "id-5", parentId : "id-4"},    {id : "id-6", parentId : "id-4"},    {id : "id-7", parentId : "id-0"},    {id : "id-8", parentId : "id-1"},    {id : "id-9", parentId : "id-7"},    {id : "id-10", parentId : "id-1"},    {id : "id-11", parentId : "id-1"},    {id : "id-12", parentId : "id-1"}];var outputArray = levelAndSort(someData, startingLevel);

输出：

注意

如果更改输入顺序，则排序会有所不同，但是仍然是正确的（即，按级别顺序，按同级分组）。