一个扁平的json到一个分组/合并的json

Question

例如：

来自

[{
        "SchoolYear": 2017,
        "Type": "cat 1",
        "Count": 7236,
        "total": 43864,
        "Percentage": 16.50
    },
    {
        "SchoolYear": 2017,
        "Type": "cat 2",
        "Count": 36628,
        "total": 43864,
        "Percentage": 83.50
    }
]

到

[{
        "SchoolYear": 2017,
        "cat 1 count": 7236,
        "cat 2 count": 36628,
        "total": 43864,
        "cat 1 Percentage": 16.50,
        "cat 2 Percentage": 83.50
}]

Answer 1

JavaScripts Array.reduce()非常善于做这样的事情。例如：

const startValues = {
  "SchoolYear": 0,
  "cat 1 count": 0,
  "cat 2 count": 0,
  "total": 0,
  "cat 1 Percentage": 0,
  "cat 2 Percentage": 0
};

const output = input.reduce((result, reportObj) => {
  const newCount = result["total"] + reportObj.Count;
  const cat1Count = reportObj.type === "cat 1" ? reportObj.Count : 0;
  const cat2Count = reportObj.type === "cat 2" ? reportObj.Count : 0;
  const cat1Total = result["cat 1 count"] + cat1Count;
  const cat2Total = result["cat 2 count"] + cat2Count;

  // Not sure what you would want to do if the school year is different?
  result["SchoolYear"] = reportObj.SchoolYear;
  result["cat 1 count"] += cat1Count;
  result["cat 2 count"] += cat2Count;
  result["total"] += newCount;
  result["cat 1 Percentage"] = cat1Total / result["total"];
  result["cat 2 Percentage"] = cat2Total / result["total"];

  return result;
}, startValues);