在 NodeJS 中迭代嵌套对象

Question

如何迭代动态嵌套对象

{
  "2021-02-01": {
    "INR": 88.345,
    "CZK": 25.975,
    "JPY": 126.77
  },
  "2021-02-02": {
    "INR": 87.906,
    "CZK": 25.9,
    "JPY": 126.46
  },
  "2021-02-05": {
    "INR": 87.367,
    "CZK": 25.806,
    "JPY": 126.72
  }
}

注意：货币是动态的，可以更改为其他货币，例如这里是“INR, CZK, JPY”，可以更改为“USD, EUR, INR”

我需要获取对象中所有货币的所有汇率的值并将它们全部加起来

这是我的代码（它不完整，我被困在其中）

      let rates = {here is object mentioned above}
     
      //iterating over object and pushing into array rateList
      for(let keys in rates){
            rateList.push(rates[keys])
      }
      
      //iterating over rateList array to get value
      rateList.forEach((obj)=>{
          console.log(Object.keys(obj)) //by this code i'm getting keys but how do i get value and sum it up
      })

总体目标是获得所有汇率值的平均值。

Answer 1

let rates = {here is object mentioned above};//main object

var keys = Object.keys(rates);// Will return ["2021-02-01", "2021-02-02"]

for(let i = 0; i < keys.length;i++){
  var obj = rates[keys[i]];//will return nested object. {"INR": 88.345,"CZK": 25.975,"JPY": 126.77
  }
}

Answer 2

更新答案

根据 OP 在下面的评论，仍然有一种简写方式来完成要求：

const rates = {
  "2021-02-01": {
    "INR": 88.345,
    "CZK": 25.975,
    "JPY": 126.77
  },
  "2021-02-02": {
    "INR": 87.906,
    "CZK": 25.9,
    "JPY": 126.46
  },
  "2021-02-05": {
    "INR": 87.367,
    "CZK": 25.806,
    "JPY": 126.72
  }
};

var returnObject = {};

Object.values(rates).forEach(childObject => { // loop all child objects within parent `rates` object:
    for (const [key, value] of Object.entries(childObject)) // extract each key=>value pair
      returnObject[key] = typeof returnObject[key] === 'undefined' ? value : returnObject[key] + value; // track it in `returnObject` - checks if the currency code already exists as a key in returnObject - if so, sums the current value and all previously-encountered values - if it doesn't already exist as a key in returnObject, sets the key to the current value
});

console.dir(returnObject);

原答案

执行此操作的一种简写方式是：

const rates = {
  "2021-02-01": {
    "INR": 88.345,
    "CZK": 25.975,
    "JPY": 126.77
  },
  "2021-02-02": {
    "INR": 87.906,
    "CZK": 25.9,
    "JPY": 126.46
  },
  "2021-02-05": {
    "INR": 87.367,
    "CZK": 25.806,
    "JPY": 126.72
  }
};

for (var key of Object.keys(rates)) { // loop all dates in parent `rates` object:
    rates[key] = Object.values(rates[key]).reduce((acc, cv) => acc += cv); // extract the values for all keys in the child Object into an Array, then use reduce() to sum the values; finally, replace the initial child object with the float result of the summation
}
console.dir(rates);

进一步阅读：

• Object.values()
• Array.prototype.reduce()

Answer 3

试试吧

let rates = {
  "2021-02-01": {
    "INR": 88.345,
    "CZK": 25.975,
    "JPY": 126.77
  },
  "2021-02-02": {
    "INR": 87.906,
    "CZK": 25.9,
    "JPY": 126.46
  },
  "2021-02-05": {
    "INR": 87.367,
    "CZK": 25.806,
    "JPY": 126.72
  }
}
let rateList = {};
let avarage = {}
//iterating over object and pushing into array rateList
for(let keys in rates){   
   Object.keys(rates[keys]).forEach((name , index)=>{
     if(rateList[name]){
    
      rateList[name]["avg"]  = (rateList[name]["avg"] + Object.values(rates[keys])[index] )/2
      rateList[name]["sum"]  += Object.values(rates[keys])[index]

     }
     else{
      let obj = {}
      obj.name = name;
      obj.sum =  Object.values(rates[keys])[index];
      obj.avg = Object.values(rates[keys])[index];
      rateList[name] = obj
     }
   }) 
}
rateList = Object.values(rateList)
console.log(rateList);

Answer 4

这是一个使用object-scan的迭代解决方案

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

const data = { '2021-02-01': { INR: 88.345, CZK: 25.975, JPY: 126.77 }, '2021-02-02': { INR: 87.906, CZK: 25.9, JPY: 126.46 }, '2021-02-05': { INR: 87.367, CZK: 25.806, JPY: 126.72 } };

const aggregate = objectScan(['*.*'], {
  rtn: 'context',
  beforeFn: (state) => {
    // eslint-disable-next-line no-param-reassign
    state.context = {};
  },
  filterFn: ({ property, value, context }) => {
    if (!(property in context)) {
      context[property] = 0;
    }
    context[property] += value;
  }
});

console.log(aggregate(data));
// => { JPY: 379.95, CZK: 77.68100000000001, INR: 263.61800000000005 }

.as-console-wrapper {max-height: 100% !important; top: 0}

<script src="https://bundle.run/object-scan@16.0.2"></script>

免责声明：我是object-scan的作者