Javascript：使用 groupBy 將對象列表轉換為嵌套對象列表

Question

這是我正在使用的 JavaScript 對象的列表：

var filtered = [
{'faculty': 'Faculty of Sciences',
 'degree': 'bachelor',
 'majorName': 'Computer Science'},

{'faculty': 'Faculty of Sciences',
 'degree': 'bachelor',
 'majorName': 'Business Computing'},

{'faculty': 'Faculty of Sciences',
 'degree': 'masters',
 'majorName': 'Computer Science'},

{'faculty': 'Faculty of Sciences',
 'degree': 'masters',
 'majorName': 'Business Computing'},

{'faculty': 'School of Arts',
 'degree': 'bachelor',
 'majorName': 'Graphic Design'},

{'faculty': 'School of Arts',
 'degree': 'bachelor',
 'majorName': 'Media and Communication'},

{'faculty': 'School of Arts',
 'degree': 'masters',
 'majorName': 'Musicology'},

{'faculty': 'School of Arts',
 'degree': 'masters',
 'majorName': 'Media'}]

我想通過對教師和學位進行分組，將其轉換為嵌套對象列表。

請運行它以查看我當前的結果是什么：

 var filtered = [{ 'faculty': 'Faculty of Sciences', 'degree': 'bachelor', 'majorName': 'Computer Science' }, { 'faculty': 'Faculty of Sciences', 'degree': 'bachelor', 'majorName': 'Business Computing' }, { 'faculty': 'Faculty of Sciences', 'degree': 'masters', 'majorName': 'Computer Science' }, { 'faculty': 'Faculty of Sciences', 'degree': 'masters', 'majorName': 'Business Computing' }, { 'faculty': 'School of Arts', 'degree': 'bachelor', 'majorName': 'Graphic Design' }, { 'faculty': 'School of Arts', 'degree': 'bachelor', 'majorName': 'Media and Communication' }, { 'faculty': 'School of Arts', 'degree': 'masters', 'majorName': 'Musicology' }, { 'faculty': 'School of Arts', 'degree': 'masters', 'majorName': 'Media' } ] var grouped = _.mapValues(_.groupBy(filtered, 'faculty'), flist => flist.map(filtered => _.omit(filtered, 'faculty'))); _.forEach(grouped, function(value, key) { grouped[key] = _.groupBy(grouped[key], function(item) { return item.degree; }); }); console.log(grouped);

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.20/lodash.min.js"></script>

我怎樣才能省略留下的“度”屬性？ 並將“majorName”屬性的值保留在屬於生成的學位屬性的列表中？

最終結果可能是這樣的：

{
"Faculty of Sciences": {
    "bachelor": ["Computer Science", "Business Computing"],
    "masters": ["Computer Science", "Business Computing"]
},
"School of Arts": {
    "bachelor": ["Graphic Design", "Media and Communication"],
    "masters": ["Musicology", "Media"]
}
}

謝謝：）

Answer 1

使用reduce() 、 解構和邏輯無效賦值 (??=)為您提供了一個簡潔的 vanilla 解決方案。

 const filtered = [{ 'faculty': 'Faculty of Sciences', 'degree': 'bachelor', 'majorName': 'Computer Science' }, { 'faculty': 'Faculty of Sciences', 'degree': 'bachelor', 'majorName': 'Business Computing' }, { 'faculty': 'Faculty of Sciences', 'degree': 'masters', 'majorName': 'Computer Science' }, { 'faculty': 'Faculty of Sciences', 'degree': 'masters', 'majorName': 'Business Computing' }, { 'faculty': 'School of Arts', 'degree': 'bachelor', 'majorName': 'Graphic Design' }, { 'faculty': 'School of Arts', 'degree': 'bachelor', 'majorName': 'Media and Communication' }, { 'faculty': 'School of Arts', 'degree': 'masters', 'majorName': 'Musicology' }, { 'faculty': 'School of Arts', 'degree': 'masters', 'majorName': 'Media' }], groupedObjs = filtered.reduce((a, { faculty, degree, ...rest }) => (((a[faculty]??= { [degree]: [] })[degree]??= []).push({...rest }), a), {}), groupedStrings = filtered.reduce((a, { faculty, degree, majorName }) => (((a[faculty]??= { [degree]: [] })[degree]??= []).push(majorName), a), {}); console.log(groupedStrings); console.log(groupedObjs);

 .as-console-wrapper { max-height: 100%;important: top; 0; }

或沒有邏輯無效分配...

 const filtered = [{ 'faculty': 'Faculty of Sciences', 'degree': 'bachelor', 'majorName': 'Computer Science' }, { 'faculty': 'Faculty of Sciences', 'degree': 'bachelor', 'majorName': 'Business Computing' }, { 'faculty': 'Faculty of Sciences', 'degree': 'masters', 'majorName': 'Computer Science' }, { 'faculty': 'Faculty of Sciences', 'degree': 'masters', 'majorName': 'Business Computing' }, { 'faculty': 'School of Arts', 'degree': 'bachelor', 'majorName': 'Graphic Design' }, { 'faculty': 'School of Arts', 'degree': 'bachelor', 'majorName': 'Media and Communication' }, { 'faculty': 'School of Arts', 'degree': 'masters', 'majorName': 'Musicology' }, { 'faculty': 'School of Arts', 'degree': 'masters', 'majorName': 'Media' }], groupedObjs = filtered.reduce((a, { faculty, degree, ...rest }) => { a[faculty] = a[faculty] || { [degree]: [] }; (a[faculty][degree] = a[faculty][degree] || []).push({...rest }); return a }, {}), groupedStrings = filtered.reduce((a, { faculty, degree, majorName }) => { a[faculty] = a[faculty] || { [degree]: [] }; (a[faculty][degree] = a[faculty][degree] || []).push(majorName); return a }, {}); console.log(groupedStrings); console.log(groupedObjs);

 .as-console-wrapper { max-height: 100%;important: top; 0; }

Answer 2

您可以將.map中的每個 arrays 再次設置為僅 select majorName字段。

這是一個例子

 const filtered = [{ 'faculty': 'Faculty of Sciences', 'degree': 'bachelor', 'majorName': 'Computer Science' }, { 'faculty': 'Faculty of Sciences', 'degree': 'bachelor', 'majorName': 'Business Computing' }, { 'faculty': 'Faculty of Sciences', 'degree': 'masters', 'majorName': 'Computer Science' }, { 'faculty': 'Faculty of Sciences', 'degree': 'masters', 'majorName': 'Business Computing' }, { 'faculty': 'School of Arts', 'degree': 'bachelor', 'majorName': 'Graphic Design' }, { 'faculty': 'School of Arts', 'degree': 'bachelor', 'majorName': 'Media and Communication' }, { 'faculty': 'School of Arts', 'degree': 'masters', 'majorName': 'Musicology' }, { 'faculty': 'School of Arts', 'degree': 'masters', 'majorName': 'Media' }]; const grouped = _(filtered).groupBy('faculty').mapValues(l => _(l).map(o => _.omit(o, 'faculty')).groupBy("degree").mapValues(x => _(x).map(y => y.majorName)) ) console.log(grouped);

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