js数组平铺和树形结构的转换

将一个平铺的数据转换成一个树形的数据结构

/*
    将一个平铺的数据转换成一个树形的数据结构
 config={
    id:id,     //对象id
    parentId:parentId    //父元素对象ID
    childrenList:childrenList     //树形属性名称[]
 }
 */
module.exports.convertArrayToTree = function (data,c) {

    if (!Array.isArray(data)) {
        throw new TypeError('array-unique expects an array.');
    }

    let config = {
        id:c.id?c.id:"id",
        parentId:c.parentId?c.parentId:"parentId",
        childrenList:c.childrenList?c.childrenList:"childrenList",
    };

    var childrenListMap = {};   //
    var nodeIds = {};   //将每一个数据项存储为一个对象
    var tree = [], count = 0, total = 0;    // tree 返回数据

    for (let d of data) {       //求出子元素列表对象
        let parentId = d[config.parentId];
        if (childrenListMap[parentId] == null) {
            childrenListMap[parentId] = [];
        }
        nodeIds[d[config.id]] = d;
        childrenListMap[parentId].push(d);
    }

    total = Object.keys(childrenListMap).length;    //总共需要几次操作

    for (let d of data) {      //初始化tree
        let parentId = d[config.parentId];
        if (nodeIds[parentId] == null) {
            tree.push(d);
        }
    }

    for (let t of tree) {
        if (count == total) {
            break;
        }
        adaptToChildrenList(t);
    }

    function adaptToChildrenList(o) {      //开始拼接数据
        if (childrenListMap[o[config.id]] !== null) {
            o[config.childrenList] = childrenListMap[o[config.id]];
            count++;
            if (count == total) {
                return;
            }
        }
        if (o[config.childrenList]) {
            for (let c of o[config.childrenList]) {
                if (count == total) {
                    break;
                }
                adaptToChildrenList(c);
            }
        }
    }
    return tree;
};

export function construct(nodes, config) {
    const id = config && config.id || 'id'
    const pid = config && config.pid || 'parentid'
    const children = config && config.children || 'children'

    const idMap = {}
    const jsonTree = []

    nodes.forEach((v) => { v && (idMap[v[id]] = v) })
    nodes.forEach((v) => {
        if (v) {
            let parent = idMap[v[pid]]
            if (parent) {
                !parent[children] && (parent[children] = [])
                parent[children].push(v)
            } else {
                jsonTree.push(v)
            }
        }
    })

    return jsonTree
}

将树形结构的数组转换成平铺的数组

/*
   将树形结构的数组转换成平铺的数组
 */

module.exports.convertTreeToArray = function (data,c) {

    if (!Array.isArray(data)) {
        throw new TypeError('array-unique expects an array.');
    }


    let config = {
        needDelete:c.needDelete?c.needDelete:false,
        childrenList:c.childrenList?c.childrenList:"childrenList"
    };

    let array = [];

    function convert(data) {
        let n = Object.assign({},data);
        config.needDelete && delete n[config.childrenList];
        array.push(n);

        if(data[config.childrenList]){
            for(let c of data[config.childrenList]){
                convert(c);
            }
        }
    }
    for(let d of data){
        convert(d);
    }

    return array;
};

export function destruct(forest, config) {
    const id = config && config.id || 'id'
    const pid = config && config.pid || 'pid'
    const children = config && config.children || 'children'

    function flatTree(tree) {
        const queue = [tree]
        const result = []
        while (queue.length) {
            let currentNode = queue.shift()
            if (currentNode.hasOwnProperty(id)) {
                if (!currentNode.hasOwnProperty(pid)) {
                    currentNode = { ...currentNode, [pid]: null }
                }
                if (currentNode[children]) {
                    currentNode[children].forEach((v) => { v && queue.push({ ...v, [pid]: currentNode[id] }) })
                }
                result.push(currentNode)
                delete currentNode[children]
            } else {
                throw new Error('you need to specify the [id] of the json tree')
            }
        }
        return result
    }

    if (Array.isArray(forest)) {
        return forest.map((v) => flatTree(v)).reduce((pre, cur) => pre.concat(cur))
    } else {
        return flatTree(forest)
    }
}