如何在 JavaScript 中按字段将数据分组到子数组中

Question

我有一个如下所示的数组。我想按天字段对这个数组进行分组。

input_array = [{
  "name": "alagu",
  "day": "monday",
  "time": "morning",
  "task": "studying"
}, {
  "name": "alagu",
  "day": "monday",
  "time": "evening",
  "task": "playing"
}, {
  "name": "alagu",
  "day": "monday",
  "time": "night",
  "task": "sleeping"
}, {
  "name": "alagu",
  "day": "sunday",
  "time": "morning",
  "task": "playing"
}, {
  "name": "alagu",
  "day": "sunday",
  "time": "evening",
  "task": "playing"
}, {
  "name": "alagu",
  "day": "sunday",
  "time": "night",
  "task": "sleeping"
}]

我希望结果类似于下面的数组。

result_array = [{
  "name": "alagu",
  "day": "monday",
  "schedule": [
    { "time": "morning", "task": "studying" },
    { "time": "evening", "task": "playing"  },
    { "time": "evening", "task": "sleeping" }
  ]
}, {
  "name": "alagu",
  "day": "sunday",
  "schedule": [
    { "time": "morning", "task": "playing"  },
    { "time": "evening", "task": "playing"  },
    { "time": "night",   "task": "sleeping" }
  ]
}]

我的意思是我想按天分组，然后我必须制作包含时间和任务元素的子数组时间表。请帮忙。

Answer 1

您可以像这样使用 reduce 函数：

const input_array = [{
  "name": "alagu",
  "day": "monday",
  "time": "morning",
  "task": "studying"
}, {
  "name": "alagu",
  "day": "monday",
  "time": "evening",
  "task": "playing"
}, {
  "name": "alagu",
  "day": "monday",
  "time": "night",
  "task": "sleeping"
}, {
  "name": "alagu",
  "day": "sunday",
  "time": "morning",
  "task": "playing"
}, {
  "name": "alagu",
  "day": "sunday",
  "time": "evening",
  "task": "playing"
}, {
  "name": "alagu",
  "day": "sunday",
  "time": "night",
  "task": "sleeping"
}]

const result_array = Object.entries(input_array.reduce((acc, curr) => {
  return {
    ...acc,
    [curr.day]: curr.day in acc ? [...acc[curr.day], curr] : [curr]
  }
}, {})).map(([key, value]) => ({
  name: value[0].name,
  day: key,
  schedule: value.map(val => ({
    time: val.time,
    task: val.task
  }))
}))

console.log(result_array)

Answer 2

要通过 foreach 和 map 函数从示例数据中获取所需的结果：

const input_array = [{ "name":"alagu", "day":"monday", "time":"morning", "task":"studying" }, 
               { "name":"alagu", "day":"monday", "time":"evening", "task":"playing" },
               { "name":"alagu", "day":"monday", "time":"night", "task":"sleeping" },
               { "name":"alagu", "day":"sunday", "time":"morning", "task":"playing" },
               { "name":"alagu", "day":"sunday", "time":"evening", "task":"playing" }, 
               { "name":"alagu", "day":"sunday", "time":"night", "task":"sleeping" }]

const result = {};

inputArray.forEach(item => {
    const { name, day, time, task } = item;
    if (!result[day]) {
        result[day] = { name, day, schedule: [] };
    }
    result[day].schedule.push({ time, task });
});

const resultArray = Object.keys(result).map(key => result[key]);

console.log(resultArray);

结果 ：

[
   {
      "name":"alagu",
      "day":"monday",
      "schedule":[
         {
            "time":"morning",
            "task":"studying"
         },
         {
            "time":"evening",
            "task":"playing"
         },
         {
            "time":"night",
            "task":"sleeping"
         }
      ]
   },
   {
      "name":"alagu",
      "day":"sunday",
      "schedule":[
         {
            "time":"morning",
            "task":"playing"
         },
         {
            "time":"evening",
            "task":"playing"
         },
         {
            "time":"night",
            "task":"sleeping"
         }
      ]
   }
]