按对象数组中的公共属性对项目进行分组答案

【问题标题】：Group items by common property in array of objects按对象数组中的公共属性对项目进行分组
【发布时间】：2021-10-18 13:14:24
【问题描述】：

我正在寻找一种在 JS 中重新排列对象数组的有效方法。我需要将每个对象的两个参数组合成一个对象，其中gwdetailsid 的值是相同的。

初始数组：

{
  "data": [
    {
      "gwdetailsid": "gw1",
      "gwpname": "username",
      "gwpvalue": "transalis"
    },
    {
      "gwdetailsid": "gw1",
      "gwpname": "password",
      "gwpvalue": "secure_password@1"
    },
    {
      "gwdetailsid": "gw2",
      "gwpname": "username",
      "gwpvalue": "tesco"
    },
    {
      "gwdetailsid": "gw2",
      "gwpname": "password",
      "gwpvalue": "lemon_farmer_2"
    }
  ]
}

所需的输出数组：

{
  "gateways": [
    {
      "gwdetailsid": "gw1",
      "username": "transalis",
      "password": "secure_password@1"
    },
    {
      "gwdetailsid": "gw2",
      "username": "tesco",
      "password": "lemon_farmer_2"
    }
  ]
}

【问题讨论】：

到目前为止你尝试过什么？您如何对解决方案进行基准测试？
efficient way to rearrange an array of objects in JS。请发布您尝试过的代码，以便我们提高效率。

标签： javascript arrays json object

【解决方案1】：

实际上，您的任务归结为将data 数组转换为gateways 数组。

您可以使用Array.prototype.reduce() 来完成这种工作，以gwdetailsid 属性为键构建Map，然后提取.values() 中的Map：

const data = [{gwdetailsid:"gw1",gwpname:"username",gwpvalue:"transalis"},{gwdetailsid:"gw1",gwpname:"password",gwpvalue:"secure_password@1"},{gwdetailsid:"gw2",gwpname:"username",gwpvalue:"tesco"},{gwdetailsid:"gw2",gwpname:"password",gwpvalue:"lemon_farmer_2"}],
      
      gateways = [...data
        .reduce((acc, {gwdetailsid, gwpname, gwpvalue} ) => {
          const group = acc.get(gwdetailsid)
          group
            ? group[gwpname] = gwpvalue
            : acc.set(gwdetailsid, {gwdetailsid, [gwpname]: gwpvalue})
          return acc
        }, new Map)
        .values()
      ]
      
console.log(gateways)

.as-console-wrapper{min-height:100%;}

【讨论】：