将此 json 转换为正确的格式链 flatten groupby

Question

我已经尝试了很长时间来完成这项工作，但对于我认为非常简单的事情仍然没有答案，试图对类型进行分组和计数，我有这个：

[
  {
    "type": "TypeOne",
    "day": "2016-07-07"
  },
  {
    "type": "TypeOne",
    "day": "2016-07-07"
  },
  {
    "type": "TypeTwo",
    "day": "2016-07-07"
  },
  {
    "type": "TypeTwo",
    "day": "2016-07-08"
  },
  {
    "type": "TypeTwo",
    "day": "2016-07-08"
  },
  {
    "type": "TypeThree",
    "day": "2016-07-08"
  },
  {
    "type": "TypeThree",
    "day": "2016-07-09"
  },
  {
    "type": "TypeFour",
    "day": "2016-07-09"
  },
  {
    "type": "TypeTwo",
    "day": "2016-07-09"
  },
  {
    "type": "TypeThree",
    "day": "2016-07-09"
  },
  {
    "type": "TypeThree",
    "day": "2016-07-09"
  },
  {
    "type": "TypeFour",
    "day": "2016-07-09"
  }
]

我需要能够按日期计算 Type 的出现次数并将其转换为这种结构：

[
  {
     "date":"2016-07-07"
    ,"TypeOne":2
    ,"TypeTwo":1
    ,"count":3
  },
  {
     "date":"2016-07-08"
    ,"TypeTwo":2
    ,"TypeThree":1
    ,"count":3
  },
  {
     "date":"2016-07-09"
    ,"TypeTwo":1
    ,"TypeThree":3
    ,"TypeFour":2
    ,"count":6
  }
]

我一直试图让它与下划线、链、groupBy 和地图一起工作，但无法实现。任何方向表示赞赏。

Answer 1

只需遍历结构并聚合值：

var dates = [
  {
    "type": "TypeOne",
    "day": "2016-07-07"
  },
  {
    "type": "TypeOne",
    "day": "2016-07-07"
  },
  {
    "type": "TypeTwo",
    "day": "2016-07-07"
  },
  {
    "type": "TypeTwo",
    "day": "2016-07-08"
  },
  {
    "type": "TypeTwo",
    "day": "2016-07-08"
  },
  {
    "type": "TypeThree",
    "day": "2016-07-08"
  },
  {
    "type": "TypeThree",
    "day": "2016-07-09"
  },
  {
    "type": "TypeFour",
    "day": "2016-07-09"
  },
  {
    "type": "TypeTwo",
    "day": "2016-07-09"
  },
  {
    "type": "TypeThree",
    "day": "2016-07-09"
  },
  {
    "type": "TypeThree",
    "day": "2016-07-09"
  },
  {
    "type": "TypeFour",
    "day": "2016-07-09"
  }
];

var result = [];

dates.forEach(function(d) {
  var date = result.find(function(da) { return da.date === d.day; });
  if (!date) {
    date = { date: d.day, count: 0 };
    result.push(date);
  }
  
  date.count++;
  if(!date[d.type]) {
    date[d.type] = 1;
  } else {
    date[d.type]++;
  }
});

console.log(result);

将此 json 转换为正确的格式链 flatten groupby

Getting this json into the correct format chain flatten groupby

format

json

underscore.js