一、数组转树

let arr = [{
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "111",
            "bdictDesc": "测试1",
            "bparentCode": "0",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "222",
            "bdictDesc": "测试2",
            "bparentCode": "0",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "333",
            "bdictDesc": "测试3",
            "bparentCode": "0",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "444",
            "bdictDesc": "测试4",
            "bparentCode": "0",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "555",
            "bdictDesc": "测试5",
            "bparentCode": "0",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA",
            "bdictDesc": "测试6",
            "bparentCode": "0",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA01",
            "bdictDesc": "测试7",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA0101",
            "bdictDesc": "测试8",
            "bparentCode": "DOCA01",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA0102",
            "bdictDesc": "测试9",
            "bparentCode": "DOCA01",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA0103",
            "bdictDesc": "测试10",
            "bparentCode": "DOCA01",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA02",
            "bdictDesc": "测试11",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA03",
            "bdictDesc": "测试12",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA0301",
            "bdictDesc": "测试13",
            "bparentCode": "DOCA03",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA0302",
            "bdictDesc": "测试14",
            "bparentCode": "DOCA03",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA04",
            "bdictDesc": "测试15",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA05",
            "bdictDesc": "测试16",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA06",
            "bdictDesc": "测试17",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA07",
            "bdictDesc": "测试18",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA08",
            "bdictDesc": "测试19",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA09",
            "bdictDesc": "测试20",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, {
            "categoryCode": "90000",
            "categoryCnName": "A1级别",
            "bdictCode": "DOCA10",
            "bdictDesc": "测试21",
            "bparentCode": "DOCA",
            "validStatus": "1"
        }, ]

        function arrayToTree(list, parentID) {
            const child = function(pareID) {
                //先定义一个数组，用于存储所查到的子元素
                const childs = [];
                //循环数组
                for (let i = 0; i < list.length; i++) {
                    //如果数组其中一项的bparentCode等于传入的，说明这一项是传入的子元素，把他push进数组，然后重复递归自己找该项的子元素
                    if (list[i].bparentCode === pareID) {
                        if (child(list[i].bdictCode).length > 0) {
                            list[i].children = child(list[i].bdictCode);
                        }
                        childs.push(list[i]);
                    }
                }
                //最后将查到的所有子元素返回
                return childs;
            };
            return child(parentID);
        }
        let res = arrayToTree(arr, '0')
        console.log(res);

二、树转数组

树转数组，实现的要点还是在于递归查找，定义一个空数组，去接收没有children属性的每一项

        let treeRes = [];

        function tree2arr(res) {
            res.forEach(item => {
                if (!item.children) {
                    treeRes.push(item)
                } else {
                    tree2arr(item.children)
                }
            })
        }
        // 此处的res取的是上边的数组转树的结果
        tree2arr(res)
        console.log(treeRes);