javascript - 将 JSON "rows"与 "colums"合并到新对象中

Question

我有一个看起来像这样的 JSON 对象数组

 [
    {"PM":"Jane","e":"j@nunya.com","h":"15.00","w":"10/30/2016 12:00:00 AM","c":"John","p":"Happy Town USA"},
    {"PM":"Jane","e":"j@nunya.com","h":"11.00","w":"11/06/2016 12:00:00 AM","c":"John","p":"Happy Town USA"},
    {"PM":"Jill","e":"j@nunya.com","h":"21.00","w":"10/30/2016 12:00:00 AM","c":"John","p":"Sad Town USA"},
    {"PM":"Jill","e":"j@nunya.com","h":"12.00","w":"11/06/2016 12:00:00 AM","c":"John","p":"Sad Town USA"}
 ]

查看给定 PM、e、p、c 组合的所有“列”数据，除了 w 和 h 字段外，数据相同。我需要将这些数据转换为一个看起来像这样的新对象。

[
    {PM:"Jane",e:"j@nunya.com",c:"John",p:"Happy Town USA",
     Details:[{"w":"10/30/2016","h":"15.00"},{"w":"11/06/2016","h":"11.00"}]},
    {PM:"Jill",e:"j@nunya.com",c:"John",p:"Sad Town USA",
    Details:[{"w":"10/30/2016","h":"21.00"},{"w":"11/06/2016","h":"12.00"}]}
]

这有点像在 SQL 查询中从行创建列，不幸的是我对源数据几乎没有控制权，所以这不是一个选项。

Answer 1

您想要使用 reduce 在 JavaScript 中完成这些类型的转换:

var arr = /* your array of objects goes here */;

var results = Object.values(arr.reduce(function(obj, row) {
  var pm = row.PM;

  // here we check to see if we already have an aggregator for that pm
  if (!obj[pm]) {
    obj[pm] = {
      PM: pm,
      e: row.e,
      c: row.c,
      p: row.p
      Details: []
    };
  }

  // now we need to add a record to the Details
  obj[pm].Details.push({ w: row.w, h: row.h });

  // common mistake using reduce is to forget 
  // to return the accumulator
  return obj;
}, {}));

您可以使用 JSON.stringify 转换回 JSON 字符串。请注意，Object.values 尚未在每个 JavaScript 环境中实现，您可能需要对其进行填充。