树形结构转换

function arrayToTree(nodes, setting) {
    var idKey = setting.idKey,
        pIdKey = setting.pIdKey,
        childKey = setting.childKey;

    var result = [], // 保存结果
        nodesForId = {}; // 存放中间结果

    // 转换为属性名放置节点
    nodes.forEach(function (node) {
        var id = node[idKey];
        nodesForId[id] = node;
    });

    nodes.forEach(function (node) {
        var id = node[idKey], // 节点id
            pId = node[pIdKey], // 节点父id
            pNode = nodesForId[pId]; // 根据节点父id找出父节点
        if (pNode && id != pId) {
            // 父节点存在并且或者父节点不等于本节点
            if (!pNode[childKey])
                pNode[childKey] = [];
            pNode[childKey].push(node);
        } else {
            // 如果父节点不存在，则该节点是根节点，插入根数组
            result.push(node);
        }
    });

    return result;
}

function treeToArray(nodes, setting, pId) {
    var idKey = setting.idKey,
        pIdKey = setting.pIdKey,
        childKey = setting.childKey;

    var result = [], // 保存结果
        fn = arguments.callee;

    nodes.forEach(function (node) {
        var childNodes = node[childKey],
            id = node[idKey];

        if (pId)
            node[pIdKey] = pId;

        result.push(node);

        if (childNodes) {
            var arr = fn(childNodes, setting, id);
            // 由于每次调用函数都经过一次result=[]，因此需要调用concat来合并结果
            result = result.concat(arr);
        }
    });

    return result;
}