从Javascript类型记录中筛选的数据中添加动态数组对象

Question

我有一个动态数据，我需要从每年排序和过滤，数据如下

years: ['2018', '2019', '2020', '2021', '2022']

[
 [{name: 'event_name1', created_at: 2021-01-12 11:25:0}, {name: 'event_name1', created_at: 2021-01-14 11:25:0}, {name: 'event_name1', created_at: 2020-01-12 11:25:0}, {name: 'event_name1', created_at: 2019-11-12 11:25:0}],

 [{name: 'event_name2', created_at: 2018-01-12 11:25:0}, {name: 'event_name2', created_at: 2018-01-12 11:25:0}, {name: 'event_name2', created_at: 2021-01-12 11:25:0}, {name: 'event_name2', created_at: 2021-11-12 11:25:0},{name: 'event_name2', created_at: 2022-01-12 11:25:0}]
 
... event_name3
]

(我必须澄清，这些年份以前是根据数据资料计算的)。

我尝试过几种方法，使用映射和过滤方法以及for结构，但是，我无法过滤这样的信息。这就是我想要过滤的数据

[
{element: 'event_name1',data:[2018:0,2019:1,2020:1,2021:1,2022:0]},
{element: 'event_name2',data:[2018:2,2019:0,2020:0,2021:1,2022:1]}
]

Answer 1

没有reduce。但是maps和filter。

我假设预期的数据属性包含文本值。

​

const data = [[ { name: 'event_name1', created_at: '2021-01-12 11:25:0' },{ name: 'event_name1', created_at: '2021-01-14 11:25:0' },{ name: 'event_name1', created_at: '2020-01-12 11:25:0' },{ name: 'event_name1', created_at: '2019-11-12 11:25:0' }],[{ name: 'event_name2', created_at: '2018-01-12 11:25:0' },{ name: 'event_name2', created_at: '2018-01-12 11:25:0' },{ name: 'event_name2', created_at: '2021-01-12 11:25:0' },{ name: 'event_name2', created_at: '2021-11-12 11:25:0' },{ name: 'event_name2', created_at: '2022-01-12 11:25:0' }]];

const years = ['2018', '2019', '2020', '2021', '2022'];

const result = data.map((arr) => {
   const [{ name: element }] = arr;
   const data = years.map((year) => {
      const count = arr.filter(({ created_at }) => created_at.slice(0, 4) === year).length;
      return `${year}:${count}`;
   });
   
   return { element, data };
})


console.log(result);

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

​

Answer 2

看起来像一个使用reduce方法的场景。迭代事件的数组，并在累加器中创建/修改适当的元素。

Answer 3

给你，我的朋友

​

const baseYearsInstances = {
  '2018': 0,
  '2019': 0,
  '2020': 0,
  '2021': 0,
  '2022': 0,
};

const test = [
  [
    { name: 'event_name1', created_at: '2021-01-12 11:25:0' },
    { name: 'event_name1', created_at: '2021-01-14 11:25:0' },
    { name: 'event_name1', created_at: '2020-01-12 11:25:0' },
    { name: 'event_name1', created_at: '2019-11-12 11:25:0' },
  ],

  [
    { name: 'event_name2', created_at: '2018-01-12 11:25:0' },
    { name: 'event_name2', created_at: '2018-01-12 11:25:0' },
    { name: 'event_name2', created_at: '2021-01-12 11:25:0' },
    { name: 'event_name2', created_at: '2021-11-12 11:25:0' },
    { name: 'event_name2', created_at: '2022-01-12 11:25:0' },
  ],
];

const eventToDate = (event) => {
  const dataNotSorted = event.map((eventDate) => {
    const year = new Date(eventDate.created_at).getFullYear();
    return year;
  });

  const data = dataNotSorted.reduce(function (acc, curr) {
    return acc[curr] ? ++acc[curr] : (acc[curr] = 1), acc;
  }, {});

  return { element: event[0]?.name, data: { ...baseYearsInstances, ...data } };
};

const result = test.map(eventToDate);

console.log(result);

​