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javascript - Javascript对象数组重组

问题描述

我正在从已加入 3 个表的关系数据库中获取数据：

var btnObj2 = [
{sect_id: 1, sect_title: 'Navigation', subsect_id: 1, subsect_title:'Übersicht', btn_id: 1, btn_title: 'Inhaltsverzeichnis'},
{sect_id: 1, sect_title: 'Navigation', subsect_id: 1, subsect_title: 'Übersicht', btn_id: 2, btn_title: 'Stichwortverzeichnis'},
{sect_id: 1, sect_title: 'Navigation', subsect_id: 2, subsect_title: 'Praxisphasen', btn_id: 3, btn_title: 'Trainingserfolg'},
{sect_id: 1, sect_title: 'Navigation', subsect_id: 2, subsect_title: 'Praxisphasen', btn_id: 4, btn_title: 'Trainingsablauf'},
{sect_id: 2, sect_title: 'Modul 1', subsect_id: 3, subsect_title: 'Mentor-Gespräche', btn_id: 5, btn_title: 'Lebenszeit'},
{sect_id: 2, sect_title: 'Modul 1', subsect_id: 3, subsect_title: 'Mentor-Gespräche', btn_id: 6, btn_title: 'Lebensplanung'},
{sect_id: 2, sect_title: 'Modul 1', subsect_id: 4, subsect_title: 'Just do it', btn_id: 7, btn_title: 'Vertrauen'},
{sect_id: 2, sect_title: 'Modul 1', subsect_id: 4, subsect_title: 'Just do it', btn_id: 8, btn_title: 'Verantwortung'}
];

必须重新构建此数据，以便每个部分都包含其子部分，并且每个子部分包含其子子子部分（子子子部分是上面代码片段中的按钮）。数据库中的数据已经按照section、sub-section、subsub-section以正确的顺序返回。

输出必须如下：

var result = [
{
    sect_id: 1,
    sect_title: 'Navigation',
    subsect: [
        {
            subsect_id: 1,
            subsect_title: 'Übersicht',
            buttons: [
                {
                    btn_id: 1,
                    btn_title: 'Verantwortung'
                },
                {
                    btn_id: 2,
                    btn_title: 'Vertrauen'
                }
            ]
        },
        {
            subsect_id: 2,
            subsect_title: 'Praxisphasen',
            buttons: [
                {
                    btn_id: 3,
                    btn_title: 'Trainingserfolg'
                },
                {
                    btn_id: 4,
                    btn_title: 'Trainingsablauf'
                }
            ]
        }
    ]
},
sect_id: 2,
sect_title: 'Module 1',
//.....
];

这是我将以 PHP 方式执行的操作：

function prepareBtns(arr) {
    var sectId, subsectId = ''
    var newArr = []
    arr.forEach((item) => {
        if(sectId !== item.sect_id){
            sectId = item.sect_id
        }
        if(subsectId !== item.subsect_id){
            subsectId = item.subsect_id
        }
        //In PHP the following line does the Job
        newArr[sectId][subsectId][] = item
    })
    return newArr
}

这是我的 JS 试验之一。这导致空槽：

function prepareBtnsXY(arr) {
var newArr = [];
arr.forEach((item) => {
    if (!newArr[item.sect_id]) {

        var objToPush = {
            sectId: item.sect_id,
            sectName: item.sect_title,
            subsect: []
        };
        newArr[item.sect_id] = objToPush;
    }

    if (!newArr[item.sect_id].subsect[item.subsect_id]) {
        var subObjToPush = {
            subsectId: item.subsect_id,
            subsectName: item.subsect_title,
            buttons: []
        };
        newArr[item.sect_id].subsect[item.subsect_id] = subObjToPush;
    }

    if (!newArr[item.sect_id].subsect[item.subsect_id].buttons[item.btn_id]) {
        var btnObjToPush = {
            btnId: item.btn_id,
            btnName: item.btn_title
        };
        newArr[item.sect_id].subsect[item.subsect_id].buttons[item.btn_id] = btnObjToPush;
    }
});

return newArr
}

标签： javascriptmultidimensional-array

解决方案

您可以将所需的键存储在另一个数组中，其中每行的第一个键是分组的键值，以下键是此级别的数据键，最后一个键是子级/子级。最终数组不包含 children 值，而是undefined.

keys = [
  //  level key          level  properties        children
  // ------------  ----------------------------- ----------
    ['sect_id',    'sect_title' /* more keys */, 'subsect'],
    ['subsect_id', 'subsect_title',              'buttons'],
    ['btn_id',     'btn_title',                  undefined]
],

该算法通过获取实际数组并搜索相同的分组键和值来迭代数据并减少键。如果未找到，它将使用给定的键生成一个新级别并将其推送到数组并返回子数组以用于下一个级别。

这种方法的优点是，只需更改原始数据和相应的keys数组即可轻松维护，该数组充当分组规则集。

var data = [{ sect_id: 1, sect_title: 'Navigation', subsect_id: 1, subsect_title: 'Übersicht', btn_id: 1, btn_title: 'Inhaltsverzeichnis' }, { sect_id: 1, sect_title: 'Navigation', subsect_id: 1, subsect_title: 'Übersicht', btn_id: 2, btn_title: 'Stichwortverzeichnis' }, { sect_id: 1, sect_title: 'Navigation', subsect_id: 2, subsect_title: 'Praxisphasen', btn_id: 3, btn_title: 'Trainingserfolg' }, { sect_id: 1, sect_title: 'Navigation', subsect_id: 2, subsect_title: 'Praxisphasen', btn_id: 4, btn_title: 'Trainingsablauf' }, { sect_id: 2, sect_title: 'Modul 1', subsect_id: 3, subsect_title: 'Mentor-Gespräche', btn_id: 5, btn_title: 'Lebenszeit' }, { sect_id: 2, sect_title: 'Modul 1', subsect_id: 3, subsect_title: 'Mentor-Gespräche', btn_id: 6, btn_title: 'Lebensplanung' }, { sect_id: 2, sect_title: 'Modul 1', subsect_id: 4, subsect_title: 'Just do it', btn_id: 7, btn_title: 'Vertrauen' }, { sect_id: 2, sect_title: 'Modul 1', subsect_id: 4, subsect_title: 'Just do it', btn_id: 8, btn_title: 'Verantwortung' }],
    keys = [['sect_id', 'sect_title', 'subsect'], ['subsect_id', 'subsect_title', 'buttons'], ['btn_id', 'btn_title', undefined]],
    result = data.reduce((r, o) => {
        keys.reduce((a, k) => {
            var temp = a.find(p => o[k[0]] === p[k[0]]);
            if (!temp) {
                a.push(temp = Object.assign(
                    ...k.map((l, i, { length }) =>
                        l && { [l]: i + 1 === length ? [] : o[l] })
                ));
            }
            return temp[k[k.length - 1]];
        }, r);
        return r;
    }, []);

console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

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