用React从获取中转换数据

Question

我已经从API中检索了数据，现在试图转换数据以发送POST请求。我希望将匹配的两个用户ID分组，并将它们的公共城市放在一个数组中，而不是单独的对象中。

例如，我检索的数据如下所示：

{
    "events": [
         {
             "city": "city-1",
             "user": "d1177368-2310-11e8-9e2a-9b860a0d9039"
         },
         {
             "city": "city-2",
            "user": "d1177368-2310-11e8-9e2a-9b860a0d9039"
         }
]}

我希望我的POST请求数据看起来类似于这样：

{
    "user": {
        "d1177368-2310-11e8-9e2a-9b860a0d9039": [
            {
                "city": [
                    "city-1",
                    "city-2"
                ]
            }]}}

到目前为止，这是我对请求的反应性组件：

import React, { useEffect, useState } from "react";
import axios from "../data/axios";

export default function Events({ fetchEvents }) {
  const [events, setEvents] = useState([]);

  useEffect(() => {
    async function fetchData() {
      const requests = await axios.get(fetchEvents);
      setEvents(requests.data.events);
      return requests;
    }
    fetchData();
  }, [fetchEvents]);

//here is my issue:
  function createSessions(user, city) {
    if (user === user) {

    }
  }

谢谢

Answer 1

迭代events数组，将其还原为具有user对象属性的对象。user对象将来自events数组元素的user值作为键，并且将城市推入city数组属性中。

events.reduce(
  (result, el) => {
    if (!result.user[el.user]) {
      result.user[el.user] = [{ city: [] }];
    }
    result.user[el.user][0].city.push(el.city);
    return result;
  },
  { user: {} }
);

​

const data = {
  events: [
    {
      city: "city-1",
      user: "d1177368-2310-11e8-9e2a-9b860a0d9039"
    },
    {
      city: "city-2",
      user: "d1177368-2310-11e8-9e2a-9b860a0d9039"
    }
  ]
};

const data2 = data.events.reduce(
  (result, el) => {
    if (!result.user[el.user]) {
      result.user[el.user] = [{ city: [] }];
    }
    result.user[el.user][0].city.push(el.city);
    return result;
  },
  { user: {} }
);

console.log(data2);

​