javascript - jQuery 对象 : summing all instances of value A where value B is duplicate

Question

我有这个增值税值对象:

[
{
 "code": "2",
 "rate": "17.5%",
 "net": 0
},
{
 "code": "2",
 "rate": "17.5%",
 "net": 0
},
{
 "code": "1",
 "rate": "Zero Rated",
 "net": 0
},
{
 "code": "1",
 "rate": "Zero Rated",
 "net": 0
},
{
 "code": "4",
 "rate": "20%",
 "net": 304.7
},
{
 "code": "1",
 "rate": "Zero Rated",
 "net": 0
},
{
 "code": "4",
 "rate": "20%",
 "net": 1200.24
},
{
 "code": "4",
 "rate": "20%",
 "net": 5201.04
},
{
 "code": "4",
 "rate": "20%",
 "net": 1258.82
},
{
 "code": "4",
 "rate": "20%",
 "net": 629.41
},
{
 "code": "4",
 "rate": "20%",
 "net": 629.41
}
]

我想要做的是显示所有单独的代码及其各自值的总和，即我想将增值税代码为1的所有净值相加并显示它(代码，费率和总净值)，然后单独显示其中增值税代码为 2 等。

我尝试使用 $.each，创建一个新对象并比较两个对象，然后添加值或创建一个代码相等的新实例，但它变得困惑和困惑:

var vatAnalysisItem = [];

$.each(self.vat(), function(index) {
  $.each(self.vat()[index], function(key1, value1) {
    if(key1 == "code") {
      if(vatAnalysisItem.length === 0) {
        vatAnalysisItem.push({code: self.vat().code, rate: self.vat().rate, net: self.vat().net});
      }
      else {
        $.each(vatAnalysisItem, function(key2, value2) {
          if(key2 == "code")
            if(value in vatAnalysisItem) {
              vatAnalysisItem[net] += self.vat().net;
            }
            else {
              vatAnalysisItem.push({code: self.vat()[code], rate: self.vat().rate, net: self.vat().net});
            }
        });
      }
    }
  });
});

。我不知道该怎么做。我将使用 Knockout JS 在 View 中显示完整的值。

任何帮助将不胜感激!

Answer 1

排序顺序可能有误，请根据口味进行调整。

var vm = {
  data: ko.observableArray([]),
  cumulativeData: ko.pureComputed(function() {
    var result = {};
    vm.data().forEach(function(datum) {
      var cumul = result[datum.code];
      if (!cumul) {
        result[datum.code] = cumul = {
          code: datum.code,
          rate: datum.rate,
          net: 0
        };
      }
      cumul.net += datum.net;
    });
    return Object.keys(result).sort().map(function(code) { return result[code]; });
  })
};

ko.applyBindings(vm);

var newData = [{"code":"2","rate":"17.5%","net":0},{"code":"2","rate":"17.5%","net":0},{"code":"1","rate":"Zero Rated","net":0},{"code":"1","rate":"Zero Rated","net":0},{"code":"4","rate":"20%","net":304.7},{"code":"1","rate":"Zero Rated","net":0},{"code":"4","rate":"20%","net":1200.24},{"code":"4","rate":"20%","net":5201.04},{"code":"4","rate":"20%","net":1258.82},{"code":"4","rate":"20%","net":629.41},{"code":"4","rate":"20%","net":629.41}];
vm.data(newData);

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<table data-bind="foreach: cumulativeData">
  <tr>
    <td data-bind="text: code"></td>
    <td data-bind="text: rate"></td>
    <td data-bind="text: net"></td>
  </tr>
</table>