Discussion on: Help? .map .reduce

const sum = (a, b) => a+b;
const uniqueCategories = (array) => [...new Set(array.map(item => item.category))];

const apiResult = [
  {name: "test1", category: "Categoria1", price: 3},
  {name: "test2", category: "Categoria1", price: 13.6},
  {name: "test3", category: "Categoria2", price: 8},
  {name: "test4", category: "Categoria2", price: 8}
];

const chartData = uniqueCategories(apiResult).map(category => [
  category,
  apiResult
    .filter(item => item.category===category)
    .map(item => item.price)
    .reduce(sum)
]);
console.log(JSON.stringify(chartData));