通过对象的JS数组过滤并添加userName相同的steps值答案

【问题标题】：Filtering through JS array of objets and adding the steps value where userName is same通过对象的JS数组过滤并添加userName相同的steps值
【发布时间】：2020-07-20 12:15:27
【问题描述】：

我正在使用 JavaScript。对于专业开发人员来说，这可能相对容易一些。我想遍历对象数组并过滤具有相同用户名的对象并添加它们的步骤。以下响应是来自我的 API 的响应，

{
    "status": 1,
    "UserList": [
        {
            "_id": "5e8c04882e31eb0fa0f240dd",
            "userName": "devyansh",
            "starttime": 1586073600,
            "endtime": 1586077200,
            "steps": 1000,
            "createdTime": 1586234504,
            "__v": 0
        },
        {
            "status": "1",
            "_id": "5e8c04f82e31eb0fa0f240df",
            "userName": "devyansh",
            "starttime": 1586080800,
            "endtime": 1586084400,
            "steps": 47,
            "createdTime": 1586234616,
            "__v": 0
        },
        {
            "_id": "5e8c282e5040a21c1498d95b",
            "userName": "amit",
            "starttime": 1586170800,
            "endtime": 1586131200,
            "steps": 899,
            "createdTime": 1586243630,
            "__v": 0
        },
}

我需要使用用户名过滤这个用户列表，如果发现用户名相同，则添加步骤。这是我希望的响应方式，

{
   "status": 1,
   "finalList": [
    {
        "totalsteps": 1047,
        "list": [
            {
                "_id": "5e8c04882e31eb0fa0f240dd",
                "userName": "devyansh",
                "starttime": 1586073600,
                "endtime": 1586077200,
                "steps": 1000,
                "createdTime": 1586234504,
                "__v": 0
            },
            {
                "status": "1",
                "_id": "5e8c04f82e31eb0fa0f240df",
                "userName": "devyansh",
                "starttime": 1586080800,
                "endtime": 1586084400,
                "steps": 47,
                "createdTime": 1586234616,
                "__v": 0
            }
        ],
    },
    {
        "totalsteps": 899,
        "list": [
            "_id": "5e8c282e5040a21c1498d95b",
            "userName": "amit",
            "starttime": 1586170800,
            "endtime": 1586131200,
            "steps": 899,
            "createdTime": 1586243630,
            "__v": 0
          ],
    },
  ]
}

我已经尝试过了，但没有得到预期的结果，

var nameArray = []

  foundData.map((data) => {
     if (!nameArray.includes(data.userName)){
        nameArray.push(data.userName)
     }
  })
  console.log("nameArray",nameArray)
  var finalArray = nameArray.map((data1) => {
     return(  foundData.filter((data) => {
        return data1 === (data.userName)
        }))
     })
  console.log("finalArray",finalArray)

谢谢，提前。任何帮助深表感谢。

【问题讨论】：

这纯粹是一个算法问题，并不是一个很复杂的问题。在要求我们为您解决之前，请展示您尝试解决的方法:) 提示：您需要迭代数组才能实现它

标签： javascript arrays node.js object

【解决方案1】：

我们可以通过userName对数组进行分组，然后对steps求和，并将数组的元素推入list。所以可以做到through reduce method:

const result = obj.UserList.reduce((a, {userName, steps, ...rest})=> {
  a[userName] = a[userName] || {totalsteps: 0, list:[]};
  a[userName].totalsteps += steps;
  a[userName].list.push({userName, steps, ...rest});
  return a;
}, {})

console.log(Object.values(result));

一个例子：

let obj = {
    "status": 1,
    "UserList": [
        {
            "_id": "5e8c04882e31eb0fa0f240dd",
            "userName": "devyansh",
            "starttime": 1586073600,
            "endtime": 1586077200,
            "steps": 1000,
            "createdTime": 1586234504,
            "__v": 0
        },
        {
            "status": "1",
            "_id": "5e8c04f82e31eb0fa0f240df",
            "userName": "devyansh",
            "starttime": 1586080800,
            "endtime": 1586084400,
            "steps": 47,
            "createdTime": 1586234616,
            "__v": 0
        },
        {
            "_id": "5e8c282e5040a21c1498d95b",
            "userName": "amit",
            "starttime": 1586170800,
            "endtime": 1586131200,
            "steps": 899,
            "createdTime": 1586243630,
            "__v": 0
        }
      ]
};

const result = obj.UserList.reduce((a, {userName, steps, ...rest})=> {
  a[userName] = a[userName] || {totalsteps: 0, list:[]};
  a[userName].totalsteps += steps;
  a[userName].list.push({userName, steps, ...rest});
  return a;
}, {})

console.log(Object.values(result));

【讨论】：

【解决方案2】：

遍历用户列表，构建一个带有“用户名”键的对象。
当对象中已经存在用户名时，只需更新步骤和列表。
迭代后，获取上述对象的Object.values()，将其作为数组获取。

const format = arr => {
  const res = {};
  arr.forEach(item => {
    if (!res[item.userName]) {
      res[item.userName] = {
        totalsteps: 0,
        list: []
      };
    }
    res[item.userName].totalsteps += item.steps;
    res[item.userName].list.push(item);
  });
  return Object.values(res);
};

const resp = {
  status: 1,
  UserList: [
    {
      _id: "5e8c04882e31eb0fa0f240dd",
      userName: "devyansh",
      starttime: 1586073600,
      endtime: 1586077200,
      steps: 1000,
      createdTime: 1586234504,
      __v: 0
    },
    {
      status: "1",
      _id: "5e8c04f82e31eb0fa0f240df",
      userName: "devyansh",
      starttime: 1586080800,
      endtime: 1586084400,
      steps: 47,
      createdTime: 1586234616,
      __v: 0
    },
    {
      _id: "5e8c282e5040a21c1498d95b",
      userName: "amit",
      starttime: 1586170800,
      endtime: 1586131200,
      steps: 899,
      createdTime: 1586243630,
      __v: 0
    }
  ]
};

const result = { status: resp.status, finalList: format(resp.UserList) };

console.log(result);

【讨论】：