使用 .reduce() 将数组转换为对象

Question

我正在努力学习Array.reduce。我被赋予了以下任务：

输入数据：

const report = [
  {
    dateOfReport: "11-01-2021",
    userId: "id1",
    userMetric: { first_metric: 10, second_metric: 15 },
  },
  {
    dateOfReport: "11-01-2021",
    userId: "id2",
    userMetric: { first_metric: 9, second_metric: 14 },
  },
  {
    dateOfReport: "12-01-2021",
    userId: "id1",
    userMetric: { first_metric: 11, second_metric: 14 },
  },
  {
    dateOfReport: "12-01-2021",
    userId: "id2",
    userMetric: { first_metric: 16, second_metric: 19 },
  },
];

我需要在输出中获取这些数据

const output = [
  {
    dateOfReport: "11-01-2021",
    id1: { first_metric: 10, second_metric: 15 },
    id2: { first_metric: 9, second_metric: 14 },
  },
  {
    dateOfReport: "12-01-2021",
    id1: { first_metric: 11, second_metric: 14 },
    id2: { first_metric: 16, second_metric: 19 },
  },
];

我试着写了一些代码，但我不知道如何正确地写。我该如何解决这个问题？

代码：

 const result = report.reduce((acc, dataItem) => {
    let outputArray = [];

    if (dataItem) {
      outputArray.push({ ...dataItem, date: dataItem.dateOfReport, [dataItem.userId]: dataItem.userMetric });
    }

    return outputArray;
  });

  return result;

Answer 1

更正了逻辑

const report = [
  {
    dateOfReport: "11-01-2021",
    userId: "id1",
    userMetric: { first_metric: 10, second_metric: 15 },
  },
  {
    dateOfReport: "11-01-2021",
    userId: "id2",
    userMetric: { first_metric: 9, second_metric: 14 },
  },
  {
    dateOfReport: "12-01-2021",
    userId: "id1",
    userMetric: { first_metric: 11, second_metric: 14 },
  },
  {
    dateOfReport: "12-01-2021",
    userId: "id2",
    userMetric: { first_metric: 16, second_metric: 19 },
  },
];
const result = report.reduce((acc, dataItem) => {
  const node = acc.find(item => item.dateOfReport === dataItem.dateOfReport);
  if (node) {
    node[dataItem.userId] = dataItem.userMetric;
  } else {
    acc.push({ dateOfReport: dataItem.dateOfReport, [dataItem.userId]: dataItem.userMetric });
  }
  return acc;
}, []);

console.log(result);

使用 .reduce() 将数组转换为对象

Transform an Array into an Object using .reduce()

javascript

arrays

reduce