Cho mảng đối tượng dữ liệu nhà cung cấp. Gom nhóm theo SupplierName và Category, cộng điểm, tính trung bình.
Ví dụ
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));
Kết quả
[ { "SupplierName": "John", "Category ": "A", "Points": 22, "Average": 6 }, { "SupplierName": "Praveen", "Category ": "A", "Points": 10, "Average": 5 } ]