javascript - 如何对对象数组进行分组？

Question

我有一个对象数组，例如:

const array = [
  {
    date: '02-02-1994',
    time: '18:00',
    services: {
      first: 1,
      second: 1
    }
  },
  {
    date: '02-02-1994',
    time: '20:00',
    services: {
      first: 1,
      second: 1
    }
  },
  {
    date: '02-04-1994',
    time: '19:00',
    services: {
      first: 1,
      second: 1
    }
  },
{
  date: '02-04-1994',
  time: '19:00',
  services: {
    first: 1,
    second: 2
  }
}
]

我想按时间和日期对它进行分组并得到结果数组:

const result = [{
  date: '02-02-1994',
  time: '18:00',
  services: {
    first: 1,
    second: 1
  }
},
{
  date: '02-02-1994',
  time: '20:00',
  services: {
    first: 1,
    second: 1
  }
},
{
  date: '02-04-1994',
  time: '19:00',
  services: {
    first: 2,
    second: 3
  }
}] 

我想按日期对数组进行分组，然后按时间对数组进行分组，并在服务对象中求和。我尝试使用 reduce 按日期分组，但我不知道

Answer 1

您可以使用 reduce()方法。

const array = [{ date: '02-02-1994', time: '18:00', services: { first: 1, second: 1 } }, { date: '02-02-1994', time: '20:00', services: { first: 1, second: 1 } }, { date: '02-04-1994', time: '19:00', services: { first: 1, second: 1 } }, { date: '02-04-1994', time: '19:00', services: { first: 1, second: 2 } } ];

let result = array.reduce((arr, currentValue) => {

  let item = arr.find(item =>
    item.date === currentValue.date &&
    item.time === currentValue.time);

  if (item) {
    item.services.first += currentValue.services.first;
    item.services.second += currentValue.services.second;
  } else {
    arr.push(currentValue);
  }

  return arr;
}, []);

console.log(result);