Question

我正在使用以下代码来查询API，它可以很好地返回JSON中的嵌套值：

const obj = response.data.map(function(item) {

return [item.id, item.jobNumber];
});

示例JSON：

{
 "data": [
  {
     "id": 100,
     "jobNumber": 1,
     "jobTasks": [
        {
           "id": 12,
           "cost": {
              "amountString": 100
           },
           {
           "id": 13,
           "cost": {
              "amountString": 500
           }
         }
     }
  ]
},
  {
     "id": 101,
     "jobNumber": 2,
     "jobTasks": [
        {
           "id": 14,
           "cost": {
              "amountString": 100
           },
          {
           "id": 15,
           "cost": {
              "amountString": 200
           }
         }
     }]

}]
}

我现在想要遍历嵌套的作业任务，并为每个作业补充 item.jobTasks.cost.amountString ，以便可以返回以下内容：

JobNumber1：任务成本：600
JobNumber2：任务成本：300

Answer 1

您可以使用Array#map()创建新数组，Array#reduce()汇总amountString

＆＃13;

const apiJson = {"data":[{"id":100,"jobNumber":1,"jobTasks":[{"id":12,"cost":{"amountString":100}},{"id":13,"cost":{"amountString":500}}]},{"id":101,"jobNumber":2,"jobTasks":[{"id":14,"cost":{"amountString":100}},{"id":15,"cost":{"amountString":200}}]}]};

const output = apiJson.data.map(d=>({
  jobNumber : d.jobNumber,
  tasksCost : d.jobTasks.reduce((a,b)=>a.cost.amountString+b.cost.amountString)
}));

console.log(output);

＆＃13;

Answer 2

您可以使用接受reduce方法的callback方法。

此外，使用forEach方法迭代data个项目。

var json={
 "data": [
  {
     "id": 100,
     "jobNumber": 1,
     "jobTasks": [
           {
           "id": 12,
           "cost": {
              "amountString": 100
            }
           },
           {
           "id": 13,
           "cost": {
              "amountString": 500
            }
           }
      ]
  },
  {
     "id": 101,
     "jobNumber": 2,
     "jobTasks": [
          {
           "id": 14,
           "cost": {
              "amountString": 100
           }
           },
          {
           "id": 15,
           "cost": {
              "amountString": 200
           }
          }
    ]

}]
}
json.data.forEach(function(item){
  var sum=item.jobTasks.reduce(function(sum,elem){
     return sum+elem.cost.amountString;
  },0);
   console.log('jobNumber'+item.jobNumber+' '+sum);
});

Answer 3

首先更新您的json，＆＃34;}＆＃34;在数组数据的第二个对象的jobTasks中缺少：

   "jobTasks": [    { "id": 14,
                    "cost": {
                         "amountString": 100 
                           }
                     },
                     {
                      "id": 15,
                  "cost": {
                        "amountString": 200
                          }
                       }
                ]

现在获得输出：

i = 0,1

item.jobTasks [I] cost.amountString;

Answer 4

这是使用object-scan的解决方案。如今，我们在数据处理中经常使用它。请花一点时间将头缠住

const objectScan = require('object-scan');

const getCounts = (data) => objectScan(['data[*].jobTasks[*].cost.amountString'], {
  filterFn: ({ parents, value, context }) => {
    const jobNumber = parents[3].jobNumber;
    context[jobNumber] = (context[jobNumber] || 0) + value;
  }
})(data, {});

const apiJson = {"data":[{"id":100,"jobNumber":1,"jobTasks":[{"id":12,"cost":{"amountString":100}},{"id":13,"cost":{"amountString":500}}]},{"id":101,"jobNumber":2,"jobTasks":[{"id":14,"cost":{"amountString":100}},{"id":15,"cost":{"amountString":200}}]}]};

console.log(getCounts(apiJson));
// => { '1': 600, '2': 300 }

在JavaScript中创建嵌套对象值的SUM

4 个答案: