[英]How to convert a flat data structure into a tree-like structure?
假设我有两个辅助函数将{}的平面数组转换为树状结构。 考虑以下平面数据:
const data = [
{
"ID": 1,
"Tier_1": "DataSource1",
"Tier_2": "Area",
"Tier_3": "General",
},
{
"ID": 2,
"Tier_1": "DataSource1",
"Tier_2": "Financial",
"Tier_3": "General",
},
{
"ID": 3,
"Tier_1": "DataSource1",
"Tier_2": "Area",
"Tier_3": "General",
},
{
"ID": 4,
"Tier_1": "DataSource2",
"Tier_2": "Area",
"Tier_3": "General",
},
{
"ID": 5,
"Tier_1": "DataSource2",
"Tier_2": "Area",
"Tier_3": "Management Plan",
}
]
数据包含三行某些分层信息,我想将其转换为树状结构,如下所示(预期输出):
(最后的子节点是实际的DB对象,但是在树上分布)
const output = {
"DataSource1: {
"Area": {
{
"ID": 1,
"Tier_1": "DataSource1",
"Tier_2": "Area",
"Tier_3": "General",
},
{
"ID": 3,
"Tier_1": "DataSource1",
"Tier_2": "Area",
"Tier_3": "General",
},
},
"Financial": [
{
"ID": 2,
"Tier_1": "DataSource1",
"Tier_2": "Financial",
"Tier_3": "General",
},
]
},
"DataSource2: {
"Area": [
{
"ID": 4,
"Tier_1": "DataSource2",
"Tier_2": "Area",
"Tier_3": "General",
},
{
"ID": 5,
"Tier_1": "DataSource2",
"Tier_2": "Area",
"Tier_3": "Management Plan",
}
]
}
}
}
我实际上设法创建功能来完成这个,但我不是那么灵活(深度/暗淡是固定的,在每个函数名称中说明)
函数返回二维树:
const getDataCategoriesTwoDim = (data, mainCategory) => {
const dataFields = [...data];
let map = {};
for (let i = 0; i < dataFields.length; i += 1) {
const currentField = dataFields[i];
const currentCategory = currentField[mainCategory];
if (!map[currentCategory]) {
map[currentCategory] = [];
}
map[currentCategory].push(currentField);
}
return map;
};
函数返回三维树:
const getDataCategoriesThreeDim = (data, mainCategory, subCategory) => { // DIFF
const dataFields = [...data];
let map = {};
for (let i = 0; i < dataFields.length; i += 1) {
const currentField = dataFields[i];
const currentCategory = currentField[mainCategory];
const currentSubcategory = currentField[subCategory]; // DIFF
if (!map[currentCategory]) {
map[currentCategory] = {}; /DIFF
}
if (!map[currentCategory][currentSubcategory]) { // DIFF
map[currentCategory][currentSubcategory] = []; // DIFF
} // DIFF
map[currentCategory][currentSubcategory].push(currentField); // DIFF
}
return map;
};
你可以这样调用这两个并得到预期的结果:
getDataCategoriesTwoDim(data, 'Tier_2');
getDataCategoriesThreeDim(data, 'Tier_2', 'Tier_3');
正如您所看到的,有很多代码重复和复制粘贴。 我在评论中标出了差异。 如何将代码重写为一个函数,以便我可以设置2,3或更多维度?
您可以使用键来嵌套属性,并为最后一个键而不是对象添加数组。 稍后将对象推送到嵌套数组。
const groupBy = (data, keys) => data.reduce((r, o) => { keys .reduce((p, k, i, a) => p[o[k]] = p[o[k]] || (i + 1 === a.length ? [] : {}), r) .push(o); return r; }, Object.create(null)), data = [{ ID: 1, Tier_1: "DataSource1", Tier_2: "Area", Tier_3: "General" }, { ID: 2, Tier_1: "DataSource1", Tier_2: "Financial", Tier_3: "General" }, { ID: 3, Tier_1: "DataSource1", Tier_2: "Area", Tier_3: "General" }, { ID: 4, Tier_1: "DataSource2", Tier_2: "Area", Tier_3: "General" }, { ID: 5, Tier_1: "DataSource2", Tier_2: "Area", Tier_3: "Management Plan" }], result1 = groupBy(data, ["Tier_1", "Tier_2"]), result2 = groupBy(data, ["Tier_1", "Tier_2", "Tier_3"]); console.log(result1); console.log(result2);
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