扁平化数据json与jsonTree格式数据互相转换方法

(function test (){
    let json = [
        {id: 1, name: '1', parentId: 0},
        {id: 2, name: '2', parentId: 0},
        {id: 3, name: '3', parentId: 0},
        {id: 11, name: '11', parentId: 1},
        {id: 12, name: '12', parentId: 1},
        {id: 13, name: '13', parentId: 1},
        {id: 111, name: '111', parentId: 11},
        {id: 112, name: '112', parentId: 11},
        {id: 21, name: '21', parentId: 2},
        {id: 211, name: '211', parentId: 21},
        {id: 1111, name: '1111', parentId: 111},
    ]
    let jsonTree = jsonTOJsonTree(json, {id:'id', pid:'parentId', children:'children'})
    console.log(jsonTree);

    let json2 = jsonTreeToJson(jsonTree, {id:'id', pid:'parentId', children:'children'})
    console.log(json2);
})()

/**
 * 将扁平化数据(json)转成jsonTree格式
 * @param  {[type]} data   扁平数据
 * @param  {[type]} config {id:'id', pid:'pid', children:'children'}
 *                         id 数据里的id string类型
 *                         pid 数据里的父id string类型
 *                         children 生成结果中子节点的字段名 string类型
 * @return {[type]}        [description]
 */
function jsonTOJsonTree (data, config) {
    let id = config.id || 'id',
        pid = config.pid || 'pid',
        children = config.children || 'children',
        idMap = [],
        jsonTree = []
    data.forEach(function(v) {
        idMap[v[id]] = v
    })
    data.forEach(function(v) {
        let parent = idMap[v[pid]]
        if (parent) {
        	!parent[children] && (parent[children] = [])
        	parent[children].push(v)
        } else {
        	jsonTree.push(v)
        }
    })
    return jsonTree
}

/**
 * 将jsonTree格式数据转成扁平化(json)数据
 * @param  {[type]} data   jsonTree格式数据
 * @param  {[type]} config {id:'id', pid:'pid', children:'children'}
 *                         id 数据里的id string类型
 *                         pid 数据里的父id string类型
 *                         children 数据里子节点字段名 string类型
 * @return {[type]}        [description]
 */
function jsonTreeToJson (data, config) {
    let id = config.id || 'id',
        pid = config.pid || 'pid',
        children = config.children || 'children',
        json = []
    json = data.reduce((arr, cur) => {
        let item = Object.assign({}, cur)
        if(children in cur){
            delete item[children]
            return arr.concat([item], jsonTreeToJson(cur[children], config));
        }else {
            return arr.concat([item])
        }
    }, [])
    return json
}