对象数组 - 如何按属性对项目进行分组，并将每个分组项目中的数据压缩为 1

Question

我正在尝试对主题中描述的数组执行操作。 我已经完成的工作 - 按公共属性 + map 将每个项目的数据分组为所需的格式。 它是通过在其中使用 reduce + map function 来实现的。 现在我需要将每个分组项目属性压缩为 1 的最后一部分。我的目标是使其正常工作，理想情况下是通过扩展重组 function。

要重组的数组

const arrToRestructure = [
{
    x: "test-x1",
    y: "test-y1",
    data: [
        {id: 1, label: "label-y1-1"},
        {id: 2, label: "label-y1-2"}
    ]
},
{
    x: "test-x2",
    y: "test-y1",
    data: [
        {id: 1, label: "label-y1-3"},
        {id: 2, label: "label-y1-4"}
    ]
},
{
    x: "test-x2",
    y: "test-y2",
    data: [
        {id: 1, label: "label-y2-1"},
        {id: 2, label: "label-y2-2"}
    ]
},
]

重组 function

const restructureArr = () => {
    const restructuredArr = arrToRestructure.reduce(
        (prevVal, nextVal) => ({
        ...prevVal,
        [nextVal["y"]]: [
            ...(prevVal[nextVal["y"]] || []),
            nextVal.data.map((nextVal) => nextVal.label),
        ]})
        ,[]);

    return restructuredArr;
}

当前 output

{
    "test-y1": [
        [
            "label-y1-1",
            "label-y1-2"
        ],
        [
            "label-y1-3",
            "label-y1-4"
        ]
    ],
    "test-y2": [
        [
            "label-y2-1",
            "label-y2-2"
        ]
    ]
}

所需 output

{
    "test-y1": [
        "label-y1-1",
        "label-y1-2",
        "label-y1-3",
        "label-y1-4",
    ],
    "test-y2": [
        "label-y2-1",
        "label-y2-2"
    ]
}

Answer 1

每次只需传播Array#map结果：

const restructureArr = () => {
  const restructuredArr = arrToRestructure.reduce((prevVal, nextVal) => ({
    ...prevVal,
    [nextVal["y"]]: [
      ...(prevVal[nextVal["y"]] || []),
      ...nextVal.data.map((nextVal) => nextVal.label), // fix
    ]
  }) , []);
  return restructuredArr;
}

一些增强功能：

 const restructureArr = (arrToRestructure = []) => arrToRestructure.reduce((acc, { y, data = [] }) => ({...acc, [y]: [...(acc[y] || []), ...data.map(({ label }) => label), ] }), []); const arrToRestructure = [ { x: "test-x1", y: "test-y1", data: [ {id: 1, label: "label-y1-1"}, {id: 2, label: "label-y1-2"} ] }, { x: "test-x2", y: "test-y1", data: [ {id: 1, label: "label-y1-3"}, {id: 2, label: "label-y1-4"} ] }, { x: "test-x2", y: "test-y2", data: [ {id: 1, label: "label-y2-1"}, {id: 2, label: "label-y2-2"} ] } ]; console.log(restructureArr(arrToRestructure));

Answer 2

您可以使用array#reduce根据y值进行分组。 使用array#forEach推送所有 label 以获得相同的y值。

 const arrToRestructure = [ { x: "test-x1", y: "test-y1", data: [ {id: 1, label: "label-y1-1"}, {id: 2, label: "label-y1-2"} ] }, { x: "test-x2", y: "test-y1", data: [ {id: 1, label: "label-y1-3"}, {id: 2, label: "label-y1-4"} ] }, { x: "test-x2", y: "test-y2", data: [ {id: 1, label: "label-y2-1"}, {id: 2, label: "label-y2-2"} ] }, ], result = arrToRestructure.reduce((r, {y, data}) => { r[y]??= []; data.forEach(({label}) => r[y].push(label)); return r; },{}); console.log(result);

Answer 3

另一种解决方案是使用Object.entries和.flat() 。

 const obj = { "test-y1": [ [ "label-y1-1", "label-y1-2" ], [ "label-y1-3", "label-y1-4" ] ], "test-y2": [ [ "label-y2-1", "label-y2-2" ] ] } const e = Object.entries(obj).map(el => ({[el[0]]: el[1].flat()})) let o = Object.fromEntries(e.map(x => [Object.keys(x), Object.values(x)[0]])) console.log(o);