有人知道一种方法(lodash如果可能的话)通过对象键分组对象数组,然后根据分组创建一个新的对象数组吗?例如,我有一个汽车对象数组:

const cars = [
    {
        'make': 'audi',
        'model': 'r8',
        'year': '2012'
    }, {
        'make': 'audi',
        'model': 'rs5',
        'year': '2013'
    }, {
        'make': 'ford',
        'model': 'mustang',
        'year': '2012'
    }, {
        'make': 'ford',
        'model': 'fusion',
        'year': '2015'
    }, {
        'make': 'kia',
        'model': 'optima',
        'year': '2012'
    },
];

我想创建一个新的汽车对象数组,由make分组:

const cars = {
    'audi': [
        {
            'model': 'r8',
            'year': '2012'
        }, {
            'model': 'rs5',
            'year': '2013'
        },
    ],

    'ford': [
        {
            'model': 'mustang',
            'year': '2012'
        }, {
            'model': 'fusion',
            'year': '2015'
        }
    ],

    'kia': [
        {
            'model': 'optima',
            'year': '2012'
        }
    ]
}

当前回答

创建一个可以重用的方法

Array.prototype.groupBy = function(prop) {
      return this.reduce(function(groups, item) {
        const val = item[prop]
        groups[val] = groups[val] || []
        groups[val].push(item)
        return groups
      }, {})
    };

下面你可以根据任何标准进行分组

const groupByMake = cars.groupBy('make');
        console.log(groupByMake);

var cars = [ { 'make': 'audi', 'model': 'r8', 'year': '2012' }, { 'make': 'audi', 'model': 'rs5', 'year': '2013' }, { 'make': 'ford', 'model': 'mustang', 'year': '2012' }, { 'make': 'ford', 'model': 'fusion', 'year': '2015' }, { 'make': 'kia', 'model': 'optima', 'year': '2012' }, ]; //re-usable method Array.prototype.groupBy = function(prop) { return this.reduce(function(groups, item) { const val = item[prop] groups[val] = groups[val] || [] groups[val].push(item) return groups }, {}) }; // initiate your groupBy. Notice the recordset Cars and the field Make.... const groupByMake = cars.groupBy('make'); console.log(groupByMake); //At this point we have objects. You can use Object.keys to return an array

其他回答

Var汽车= [{ :“奥迪”, 模型:“r8”, :“2012” },{ :“奥迪”, 模型:“生活费”, :“2013” },{ :“福特”, 模型:“野马”, :“2012” },{ :“福特”, 模型:“融合”, :“2015” },{ :“克钦独立军”, 模型:“最佳状态”, :“2012” })。Reduce ((r, car) => { const { 模型中, 一年, 使 } =汽车; R [make] =[…]R [make] || [], { 模型中, 一年 }); 返回r; }, {}); console.log(汽车);

只需简单的forEach循环就可以在这里工作,不需要任何库

var cars = [ { 'make': 'audi', 'model': 'r8', 'year': '2012' }, { 'make': 'audi', 'model': 'rs5', 'year': '2013' }, { 'make': 'ford', 'model': 'mustang', 'year': '2012' }, { 'make': 'ford', 'model': 'fusion', 'year': '2015' }, { 'make': 'kia', 'model': 'optima', 'year': '2012' }, ]; let ObjMap ={}; cars.forEach(element => { var makeKey = element.make; if(!ObjMap[makeKey]) { ObjMap[makeKey] = []; } ObjMap[makeKey].push({ model: element.model, year: element.year }); }); console.log(ObjMap);

const groupBy = (array, callback) => {
  const groups = {};
  
  array.forEach((element) => {
    const groupName = callback(element);
    if (groupName in groups) {
      groups[groupName].push(element);
    } else {
      groups[groupName] = [element];
    }
  });
  
  return groups;
};

或者花哨的裤子:

(() => {
  Array.prototype.groupBy = function (callback) {
    const groups = {};
    this.forEach((element, ...args) => {
      const groupName = callback(element, ...args);
      if (groupName in groups) {
        groups[groupName].push(element);
      } else {
        groups[groupName] = [element];
      }
    });

    return groups;
  };
})();

const res = [{ name: 1 }, { name: 1 }, { name: 0 }].groupBy(({ name }) => name);

// const res = {
//   0: [{name: 0}],
//   1: [{name: 1}, {name: 1}]
// }

这是一个MDN阵列的填充。groupBy函数。

下面是您自己的groupBy函数,它是来自https://github.com/you-dont-need/You-Dont-Need-Lodash-Underscore的代码的泛化

函数groupBy(xs, f) { 返回x。减少((r, v, i, a、k = f (v)) = > ((r [k] | | (r [k] = [])) .push (v), r), {}); } Const cars = [{make: 'audi',型号:'r8',年份:'2012'},{make: 'audi',型号:'rs5',年份:'2013'},{make: 'ford',型号:'mustang',年份:'2012'},{make: 'ford',型号:'fusion',年份:'2015'},{make: 'kia',型号:'optima',年份:'2012'}]; const result = groupBy(cars, (c) => c.make); console.log(结果);

这是一个通用函数,将返回Array groupBy自己的键。

const getSectionListGroupedByKey = < T > ( property: keyof T, List: Array < T > ): Array < { title: T[keyof T];data: Array < T > } > => { const sectionList: Array < { title: T[keyof T];data: Array < T > } > = []; if (!property || !List ? .[0] ? .[property]) { return []; } const groupedTxnListMap: Map < T[keyof T], Array < T >> = List.reduce((acc, cv) => { const keyValue: T[keyof T] = cv[property]; if (acc.has(keyValue)) { acc.get(keyValue) ? .push(cv); } else { acc.set(keyValue, [cv]); } return acc; }, new Map < T[keyof T], Array < T >> ()); groupedTxnListMap.forEach((value, key) => { sectionList.push({ title: key, data: value }); }); return sectionList; }; // Example const cars = [{ 'make': 'audi', 'model': 'r8', 'year': '2012' }, { 'make': 'audi', 'model': 'rs5', 'year': '2013' }, { 'make': 'ford', 'model': 'mustang', 'year': '2012' }, { 'make': 'ford', 'model': 'fusion', 'year': '2015' }, { 'make': 'kia', 'model': 'optima', 'year': '2012' }, ]; const result = getSectionListGroupedByKey('make', cars); console.log('result: ', result)