具有屬性作為鍵的對象的對象數組

Question

我需要一些幫助來從一個對象數組中獲取對象，其中的鍵來自初始數組中對象的嵌套屬性。 這是最初的數組：

[  
   {  
      "id":{  
         "colName":"columnA",
         "recId":"123"
      },
      "desc":"this is a description for A",
      "resCode":"-1"
   },
   {  
      "id":{  
         "colName":"columnB",
         "recId":"123"
      },
      "desc":"this is a  description for B",
      "resCode":"-1"
   },
   {  
      "id":{  
         "colName":"columnC",
         "recId":"234"
      },
      "desc":"description for column c ",
      "resCode":"-1"
   }
];

我想要的輸出是這樣的：

{
    123: {
        columnA: {
            desc: "this is a description for A",
            rescode: "-1"
        }
        columnB: {
            desc: "this is a description for B",
            rescode: "-1"
        }
    },
    234: {
        columnC: {
            desc: "description for column c ",
            resCode: "-1",
        }
    }
}

我嘗試使用reduce來做到這一點，但我有一個問題。 我不知道如何（以及何時）“清除”臨時變量，因此我只能擁有屬於一個recId的列名。

  const initialArray = [ { "id": { "colName": "columnA", "recId": "123" }, "desc": "this is a description for A", "resCode": "-1" }, { "id": { "colName": "columnB", "recId": "123" }, "desc": "this is a description for B", "resCode": "-1" }, { "id": { "colName": "columnC", "recId": "234" }, "desc": "description for column c ", "resCode": "-1" } ]; let temp = {}; const mappedObj = initialArray.reduce((obj, item) => { temp[item.id.colName] = Object.assign({}, {desc: item.desc}, {resCode: item.resCode} ); obj[item.id['recId']] = Object.assign({}, temp); return obj; }, {}); console.log(mappedObj); 

Answer 1

您不需要在reduce之外維護臨時變量，您可以簡單地在reduce本身中處理相同的操作

 const initialArray = [ { "id": { "colName": "columnA", "recId": "123" }, "desc": "this is a description for A", "resCode": "-1" }, { "id": { "colName": "columnB", "recId": "123" }, "desc": "this is a description for B", "resCode": "-1" }, { "id": { "colName": "columnC", "recId": "234" }, "desc": "description for column c ", "resCode": "-1" } ]; const mappedObj = initialArray.reduce((obj, item) => { obj[item.id.recId] = {...(obj[item.id.recId] || {}), [item.id.colName]: {desc: item.desc, resCode: item.resCode}} return obj; }, {}); console.log(mappedObj);