複数のフィルターJavaScriptに基づいてJSONデータから平均を計算する

このようなオブジェクトの配列があるとします-

const arr = [
   { "SupplierName" : "John", "Category " : "A", "Points" : 3 },
   { "SupplierName" : "John", "Category " : "A", "Points" : 11 },
   { "SupplierName" : "John", "Category " : "A", "Points" : undefined },
   { "SupplierName" : "John", "Category " : "B", "Points" : 2 },
   { "SupplierName" : "John", "Category " : "B", "Points" : 6 },
   { "SupplierName" : "Praveen", "Category " : "A", "Points" : 3 },
   { "SupplierName" : "Praveen", "Category " : "A", "Points" : 7 }
];

そのような配列を1つ取り込むJavaScript関数を作成する必要があります。

関数は次のことを行う必要があります-

• 繰り返しのサプライヤを1つの一意の個別のオブジェクトにグループ化します（繰り返しとは、同じ「SupplierName」フィールドと「Category」フィールドを持つオブジェクトを意味します）。
• ポイントを合計する
• 新しい「各オブジェクトに、そのサプライヤの平均ポイントを含む平均フィールドを追加します。

したがって、最終的に出力は次のようになります-

const output = [
   { "SupplierName" : "John", "Category " : "A", "Points" : 14, "Average" : 7 },
   { "SupplierName" : "John", "Category " : "B", "Points" : 8, "Average" : 4 },
   { "SupplierName" : "Praveen", "Category " : "A", "Points" : 10, "Average" : 5 }
];

例

const arr = [
   { "SupplierName" : "John", "Category " : "A", "Points" : 3 },
   { "SupplierName" : "John", "Category " : "A", "Points" : 11 },
   { "SupplierName" : "John", "Category " : "A", "Points" : undefined },
   { "SupplierName" : "John", "Category " : "B", "Points" : 2 },
   { "SupplierName" : "John", "Category " : "B", "Points" : 6 },
   { "SupplierName" : "Praveen", "Category " : "A", "Points" : 3 },
   { "SupplierName" : "Praveen", "Category " : "A", "Points" : 7 }
];
const groupAndAverage = (arr = []) => {
   const groups = arr.reduce((acc, obj) => {
       const name = obj.SupplierName + obj.Category;
      if (acc[name]) {
         if (obj.Points) (acc[name].Points += obj.Points) && ++acc[name].Average;
      }
      else { acc[name] = obj;
         acc[name].Average = 1;
         // taking 'Average' attribute as an items counter(on the first phase)
      };
      return acc;
   }, {});
   // getting "average of Points" const res = Object.keys(groups).map( name => {       groups[name].Average = Math.round(groups[name].Points/groups[name].Average);
      return groups[name];
   });
   return res;
}; console.log(JSON.stringify(groupAndAverage(arr), undefined, 4));

出力

そして、コンソールの出力は-

[
   {
      "SupplierName": "John",
      "Category ": "A",
      "Points": 22,
      "Average": 6
   },
   {
      "SupplierName": "Praveen",
      "Category ": "A",
      "Points": 10,
      "Average": 5
   }
]