javascript - 如果日期匹配，则将数组对象过滤为另一个数组对象

Question

我有一个这样的数组:

array = [
  { team: arsenal, date: "2019-12-21T12:30:00Z" },
  { team: mancity, date: "2019-12-21T12:30:00Z" },
  { team: chelsea, date: "2019-12-21T12:30:00Z" },
  { team: liverpool, date: "2019-12-22T12:30:00Z" },
  { team: spurs, date: "2019-12-22T12:30:00Z" }
];

我想创建其他具有相同日期的数组对象，如下所示:

 array1 = [
    { team: arsenal, date: "2019-12-21T12:30:00Z" },
    { team: mancity, date: "2019-12-21T12:30:00Z" },
    { team: chelsea, date: "2019-12-21T12:30:00Z" },
  ];

  array2 = [
    { team: liverpool, date: "2019-12-22T12:30:00Z" },
    { team: spurs, date: "2019-12-22T12:30:00Z" }
  ];

我正在使用 vue.js，但我想这只是简单的 javascript 解决方案。我试过 filter 和 for 循环，我不断收到错误。也许 lodash 有解决方案？什么是最优雅的。

我的尝试:

arrayFilter() {
      for (var i = 0, dates = array.length; i < dates; i++) {
        var datearray = [];
        array.map((item, i) => {
          if (array[i] === item.date) {
            datearray.push(item.date);
          }
          console.log("datearray: ", datearray);
        });
      }
    }

Answer 1

基本上，您不需要任何库。只需使用 reduce ()。

const array = [
  { team: 'arsenal', date: "2019-12-21T12:30:00Z" },
  { team: 'mancity', date: "2019-12-21T12:30:00Z" },
  { team: 'chelsea', date: "2019-12-21T12:30:00Z" },
  { team: 'liverpool', date: "2019-12-22T12:30:00Z" },
  { team: 'spurs', date: "2019-12-22T12:30:00Z" }
]

const grouppedObjectByDate = array.reduce((acc, item) => {
  (acc[item.date] || (acc[item.date] = [])).push(item)
  return acc
}, {})

console.log(grouppedObjectByDate)
// {
//   "2019-12-21T12:30:00Z": [
//     {"team": "arsenal", "date": "2019-12-21T12:30:00Z"},
//     {"team": "mancity", "date": "2019-12-21T12:30:00Z"},
//     {"team": "chelsea", "date": "2019-12-21T12:30:00Z"}
//   ],
//   "2019-12-22T12:30:00Z": [
//     {"team": "liverpool", "date": "2019-12-22T12:30:00Z"},
//     {"team": "spurs", "date": "2019-12-22T12:30:00Z"}
//   ]
// }

console.log(Object.values(grouppedObjectByDate))
// [
//   [
//     {"team": "arsenal", "date": "2019-12-21T12:30:00Z"},
//     {"team": "mancity", "date": "2019-12-21T12:30:00Z"},
//     {"team": "chelsea", "date": "2019-12-21T12:30:00Z"}
//   ],
//   [
//     {"team": "liverpool", "date": "2019-12-22T12:30:00Z"},
//     {"team": "spurs", "date": "2019-12-22T12:30:00Z"}
//   ]
// ]