使用Angular 4 Pipes或Rxjs运算符在对象数组(json)中分组/加和属性值

问题描述

http调用的响应是这样的公司对象数组:

The response from my http call is an array of company objects like this:

response = [{
    "name": "CompanyName1",
    "registrations": [
      {
        "country": "en",
        "register": "registerType1",
        "amount": 2
      },
      {
        "country": "wa",
        "register": "registerType2",
        "amount": 1
      },{
        "country": "en",
        "register": "registerType1",
        "amount": 3
      },
       {
        "country": "sc",
        "register": "registerType3",
        "amount": 2
      },
      {
        "country": "wa",
        "register": "registerType3",
        "amount": 2
      }
    ]
  },
  {
    "name": "CompanyName2",
    "registrations": [
      {
        "country": "wa",
        "register": "registerType1",
        "amount": 3
      },
      {
        "country": "sc",
        "register": "registerType3",
        "amount": 1
      }
    ]]

如果registerType1 ||，我需要按寄存器和国家/地区将公司的注册分组/汇总为新的propertyName(registerType_12). registerType2否则保留属性名称registerTypeN.那是针对companyName1的，我需要得到这样的结果:

I need to group/sum company's registrations by register and country into a new propertyName (registerType_12) if registerType1 || registerType2 otherwise just keep property name registerTypeN. that is for companyName1 I need to get a result like this:

CompanyName1: [{country:en, registerType_12, amount:5},
              {country:wa, registerTyoe_12, amount:1,
              {country:sc, registerType3, amount:4}
              }]

推荐答案

您不需要打字稿或rxjs.可以使用纯JavaScript来实现.

You don't need typescript or rxjs for this. It can be achieved with pure javascript.

JSBin链接: https://jsbin.com/yujocofesu/edit?js,console

response.reduce((finalObj, obj)=>{
     finalObj[obj.name] = 
         obj.registrations
             .map(reg => Object.assign(reg,
                  {register: ( 
                     reg.register ==='registerType1'||
                     reg.register==='registerType2') ?
                     'registerType_12': reg.register 
                   })
              )
              .reduce(mergeSimilar, []);
     return finalObj;
   },{});


function mergeSimilar(newList, item){
  let idx = newList.findIndex( 
      i=> i.country === item.country && i.register === item.register);
  if(idx>-1){
    newList[idx].amount += item.amount;
  }else{
    newList.push(item)
  }
  return newList;
}

此响应为

{
  CompanyName1: [{
    amount: 5,
    country: "en",
    register: "registerType_12"
  }, {
    amount: 1,
    country: "wa",
    register: "registerType_12"
  }, {
    amount: 2,
    country: "sc",
    register: "registerType3"
  }, {
    amount: 2,
    country: "wa",
    register: "registerType3"
  }],
  CompanyName2: [{
    amount: 3,
    country: "wa",
    register: "registerType_12"
  }, {
    amount: 1,
    country: "sc",
    register: "registerType3"
  }]
}

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