尝试将对象数组减少为类似但总结的对象数组

Question

所以我有一个对象数组，看起来像：

dataArray = [
    {Revenue: 5, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 10, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 5, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 1, Date: "2018-06-13T00:00:00", DateString: "6/13/2018"},
    {Revenue: 4, Date: "2018-06-13T00:00:00", DateString: "6/13/2018"}
]

我需要的是将其减少到另一个看起来像的对象数组：

reducedDataArray = [
    {Revenue: 20, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 5, Date: "2018-06-13T00:00:00", DateString: "6/13/2018"}
]

基本上，如果日期相同，则需要对收入进行求和，以便不存在同一日期的多个实例。不幸的是我只限于我们的Typescript版本，所以我没有所有很酷的ES6好东西来帮助解决这个问题。我尝试过使用像reduce（）这样的东西，但我认为不知道我在做什么，这有点奇怪，这让我陷入迷茫。

任何建议或见解将不胜感激！

Answer 1

玩了一些循环，它的工作原理

dataArray = [
    {Revenue: 5, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 10, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 5, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 1, Date: "2018-06-13T00:00:00", DateString: "6/13/2018"},
    {Revenue: 4, Date: "2018-06-13T00:00:00", DateString: "6/13/2018"}
];

const getUnique=array=>{
  return array.filter((value, index, self)=> { 
      return self.indexOf(value) === index;
  });
}

let date=[];
let output=[];

for(const v of dataArray) date.push(v.Date);
for(const v of getUnique(date)){

  let revenue=0,date=v,dateString;
  for(const x of dataArray){
    if(x.Date==v) revenue+=x.Revenue;
    dateString=x.DateString;
  }

  output.push({
    Revenue:revenue,
    Date:v,
    DateString:dateString
  });

}

console.log(output);

jsfiddle link

Answer 2

您可以使用reduce创建带有日期键的对象，然后将对象转换回数组。

let dataArray = [
    {Revenue: 5, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 10, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 5, Date: "2018-06-05T00:00:00", DateString: "6/5/2018"},
    {Revenue: 1, Date: "2018-06-13T00:00:00", DateString: "6/13/2018"},
    {Revenue: 4, Date: "2018-06-13T00:00:00", DateString: "6/13/2018"}
]
// We need to specify the type parameter explicitly, as it will not be inffered from initial value 
let valuesObj = dataArray.reduce<{ [date: string]: typeof dataArray[number] }>((p, v) => {
    const existing = p[v.Date];
    if (existing) {
        existing.Revenue += v.Revenue
    } else {
        p[v.Date] = Object.assign({}, v); //Create a copy so as to not change the original when we sum 
    }
    return p;
}, {});


// You can use Object.values(valuesObj) if available 
let values = Object.keys(valuesObj).map(k => valuesaObj[k]);

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