如何按portfolio与sendType条件合并对象为结构化数组？

需求说明：
将给定的JavaScript对象数组myData，按portfolio与sendType字段进行分组合并；同一分组下，把regiserDate作为属性名，对应amount的汇总值作为属性值，最终生成一个扁平化的对象数组（非父子嵌套结构）。

原始数据 #

var myData = [{
"portfolio": "Consumer",
"regiserDate": "2021-01-27",
"sendType": "Capitalization",
"amount": 1000,
"__typename": "taxCalculation"
}, 
{
"portfolio": "Consumer",
"regiserDate": "2021-01-27",
"sendType": "Capitalization",
"amount": 3000,
"__typename": "taxCalculation"
},
{
"portfolio": "Consumer",
"regiserDate": "2021-01-27",
"sendType": "Capitalization",
"amount": 6000,
"__typename": "taxCalculation"
},
{
"portfolio": "Consumer",
"regiserDate": "2021-01-27",
"sendType": "Capitalization",
"amount": 7000,
"__typename": "taxCalculation"
},
 {
"portfolio": "Commercial",
"regiserDate": "2021-02-27",
"sendType": "Accure",
"amount": 999,
"__typename": "taxCalculation"
}, 
{
"portfolio": "Commercial",
"regiserDate": "2021-02-27",
"sendType": "Accure",
"amount": 9999,
"__typename": "taxCalculation"
},
 {
"portfolio": "Commercial",
"regiserDate": "2021-02-27",
"sendType": "Capitalization",
"amount": 3,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Commercial",
"regiserDate": "2021-01-27",
"sendType": "Accure",
"amount": 4,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Commercial",
"regiserDate": "2021-04-27",
"sendType": "Capitalization",
"amount": 6,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-05-27",
"sendType": "Capitalization",
"amount": 7,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-06-27",
"sendType": "Capitalization",
"amount": 8,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-02-27",
"sendType": "Capitalization",
"amount": 10,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-07-27",
"sendType": "payable",
"amount": 12,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-01-27",
"sendType": "Accure",
"amount": 13,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-09-27",
"sendType": "Accure",
"amount": 14,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-08-27",
"sendType": "Accure",
"amount": 16,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-09-27",
"sendType": "Accure",
"amount": 17,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-11-27",
"sendType": "Accure",
"amount": 18,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-11-27",
"sendType": "Accure",
"amount": 19,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-01-27",
"sendType": "payable",
"amount": 20,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Retail",
"regiserDate": "2021-01-27",
"sendType": "Accure",
"amount": 21,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-01-27",
"sendType": "Accure",
"amount": 22,
"__typename": "taxCalculation"
}, {
"portfolio": "Consumer",
"regiserDate": "2021-12-27",
"sendType": "Accure",
"amount": 28,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-11-27",
"sendType": "payable",
"amount": 30,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-01-27",
"sendType": "AccureAccureAccure",
"amount": 33,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-01-27",
"sendType": "AccureAccure",
"amount": 35,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-01-27",
"sendType": "Accure",
"amount": 45,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Consumer",
"regiserDate": "2021-04-27",
"sendType": "Capitalization",
"amount": 49,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Commercial",
"regiserDate": "2021-07-27",
"sendType": "payable",
"amount": 87,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Commercial",
"regiserDate": "2021-07-27",
"sendType": "Capitalization",
"amount": 81,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Commercial",
"regiserDate": "2021-08-27",
"sendType": "Accure",
"amount": 65,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Commercial",
"regiserDate": "2021-01-27",
"sendType": "payable",
"amount": 470,
"__typename": "taxCalculation"
}, 
 {
"portfolio": "Commercial",
"regiserDate": "2021-05-27",
"sendType": "payable",
"amount": 540,
"__typename": "taxCalculation"
}
];

预期结果 #

var result = [{
"portfolio": "Consumer",
"sendType": "Capitalization",
"2021-01-27": 17000,
"2021-04-27": 49,
"__typename": "taxCalculation"
}, 
{
"portfolio": "Consumer",
"sendType": "Accure",
"2021-01-27": 67,
"2021-08-27": 16,
"2021-09-27": 17,
"2021-11-27": 18,
"2021-12-27": 28,
"__typename": "taxCalculation"
},
{
"portfolio": "Consumer",
"sendType": "payable",
"2021-11-27": 30,
"__typename": "taxCalculation"
},
{
"portfolio": "Consumer",
"sendType": "AccureAccureAccure",
"2021-01-27": 33,
"__typename": "taxCalculation"
},
{
"portfolio": "Consumer",
"sendType": "AccureAccure",
"2021-01-27": 35,
"__typename": "taxCalculation"
},
{
"portfolio": "Commercial",
"sendType": "Accure",
"2021-02-27": 10998,
"2021-01-27": 4,
"2021-08-27": 65,
"__typename": "taxCalculation"
},
{
"portfolio": "Commercial",
"sendType": "Capitalization",
"2021-02-27": 3,
"2021-04-27": 6,
"2021-07-27": 81,
"__typename": "taxCalculation"
},
{
"portfolio": "Commercial",
"sendType": "payable",
"2021-07-27": 87,
"2021-01-27": 470,
"2021-05-27": 540,
"__typename": "taxCalculation"
},
{
"portfolio": "Retail",
"sendType": "Capitalization",
"2021-05-27":7,
"2021-06-27":8,
"2021-02-27":10,
"__typename": "taxCalculation"
},
{
"portfolio": "Retail",
"sendType": "payable",
"2021-07-27":12,
"2021-01-27":20,
"__typename": "taxCalculation"
},
{
"portfolio": "Retail",
"sendType": "Accure",
"2021-01-27":34,
"2021-09-27":14,
"2021-11-27":19,
"__typename": "taxCalculation"
}
];

注：原预期结果中的金额为示例占位值，上述结果为实际汇总后的数据。

实现方案 #

可以使用Array.reduce()方法完成分组与汇总，核心逻辑如下：

1. 用临时对象做映射表，以portfolio+sendType的组合字符串作为唯一键，区分不同分组。
2. 遍历原始数组元素：
   • 若映射表中无当前分组，初始化包含基础字段的对象，并添加当前日期的金额。
   • 若映射表中已有当前分组，检查对应日期属性，存在则累加金额，不存在则新增属性并赋值。
3. 最后将映射表的所有值转换为数组，得到最终结果。

代码实现 #

const result = Object.values(myData.reduce((acc, item) => {
  // 生成唯一分组标识
  const key = `${item.portfolio}-${item.sendType}`;
  
  if (!acc[key]) {
    // 初始化分组对象
    acc[key] = {
      portfolio: item.portfolio,
      sendType: item.sendType,
      __typename: item.__typename
    };
  }
  
  // 汇总对应日期的金额
  acc[key][item.regiserDate] = (acc[key][item.regiserDate] || 0) + item.amount;
  
  return acc;
}, {}));

console.log(result);

内容的提问来源于stack exchange，提问作者Jolen Qadar