javascript - 如何根据 typescript 中的键从对象中提取特定元素

Question

我有一个要求，需要根据特定键从 JSON 对象中提取元素/属性。我在这里非常困惑如何获取。

{   "metadata":{
      "lastSyncTime":"2000-11-21T16:07:53",
      "dataFromDB":true
   },
   "allocationReports":[      {
         "allocatedUserCount":100,
         "healthGoalName":"Eat Healthier",
         "segments": [
            {segmentValue: "40-49", allocatedUserCount: 2}, 
            {segmentValue: "30-39", allocatedUserCount: 13},
            {segmentValue: "20-29", allocatedUserCount: 23}
         ]
      },
      {
         "allocatedUserCount":130,
         "healthGoalName":"Feel Happier",
         "segments": [
            {segmentValue: "40-49", allocatedUserCount: 20}, 
            {segmentValue: "30-39", allocatedUserCount: 3},
            {segmentValue: "20-29", allocatedUserCount: 53}
         ]
      },
  
      {
         "allocatedUserCount":150,
         "healthGoalName":"Quit Smoking",
         "segments": [
            {segmentValue: "40-49", allocatedUserCount: 19}, 
            {segmentValue: "30-39", allocatedUserCount: 1},
            {segmentValue: "20-29", allocatedUserCount: 22},
            {segmentValue: "10-19", allocatedUserCount: 47}
         ]
      }
   ],
   "overall":{
      "usersWithGoalCount":0,
      "registeredCount":500,
      "eligibleCount":280
   }
}

我们如何根据healthgoalName提取segment数组。例如，我编写了一个以“healthGoalName”(假设戒烟)作为参数的方法。 这个方法应该返回 -

"segments": [
   {segmentValue: "40-49", allocatedUserCount: 19}, 
   {segmentValue: "30-39", allocatedUserCount: 1},
   {segmentValue: "20-29", allocatedUserCount: 22},
   {segmentValue: "10-19", allocatedUserCount: 47}
]

提前致谢。

Answer 1

我假设问题中的 JSON 显示名为 obj 的对象的内容，该对象在名为 getSegments 的方法的上下文中可用。如果情况并非如此，您需要将该对象作为第二个参数提供给该方法。

function getSegments(healthGoalName)
{
    const allocationReport = obj.allocationReports.find(allocationReport => allocationReport.healthGoalName === healthGoalName);
    return allocationReport ? allocationReport.segments : null;
}

function getSegments(healthGoalName)
{
    const allocationReport = obj.allocationReports.find(allocationReport => allocationReport.healthGoalName === healthGoalName);
    return allocationReport ? allocationReport.segments : null;
}

const obj =
{
    "metadata":{
      "lastSyncTime":"2000-11-21T16:07:53",
      "dataFromDB":true
   },
   "allocationReports":[      {
         "allocatedUserCount":100,
         "healthGoalName":"Eat Healthier",
         "segments": [
            {segmentValue: "40-49", allocatedUserCount: 2}, 
            {segmentValue: "30-39", allocatedUserCount: 13},
            {segmentValue: "20-29", allocatedUserCount: 23}
         ]
      },
      {
         "allocatedUserCount":130,
         "healthGoalName":"Feel Happier",
         "segments": [
            {segmentValue: "40-49", allocatedUserCount: 20}, 
            {segmentValue: "30-39", allocatedUserCount: 3},
            {segmentValue: "20-29", allocatedUserCount: 53}
         ]
      },
  
      {
         "allocatedUserCount":150,
         "healthGoalName":"Quit Smoking",
         "segments": [
            {segmentValue: "40-49", allocatedUserCount: 19}, 
            {segmentValue: "30-39", allocatedUserCount: 1},
            {segmentValue: "20-29", allocatedUserCount: 22},
            {segmentValue: "10-19", allocatedUserCount: 47}
         ]
      }
   ],
   "overall":{
      "usersWithGoalCount":0,
      "registeredCount":500,
      "eligibleCount":280
   }
};

const segments = getSegments("Quit Smoking");
console.log({ segments });