用节点分组 / Javascript

Question

我有一个 JS 数组，其中还包含数组，每个数组都包含一堆结构如下所示的对象。

const arr1 = [
  [{symbol: "xy", balance: 2155113}, {symbol: "asda", balance: 21231231}],
  [{symbol: "asda", balance: 6543}, {symbol: "xy", balance: 21678}]
]

我需要的是一个输出数组，它按“符号”属性对所有子数组进行分组，并将余额相加 (+)。

最后我想要一个这样的数组

[
{symbol: xy, summedBalance: 213131313}, 
{symbol: yz, summedBalance: 6788767867},
]

普通 javascript 或像 lodash 这样的模块是否可行？

Answer 1

尝试这样的事情：

const arr1 = [
  [{symbol: "xy", balance: 2155113}, {symbol: "asda", balance: 21231231}],
  [{symbol: "asda", balance: 6543}, {symbol: "xy", balance: 21678}]
]

// Some variables
const knownSymbolsArr = [];
const finalArr = [];

// First degroup your array
const degroupedArr = arr1.flat();

// Iterate and sum balances
degroupedArr.forEach(el => {
  // Unknown symbol, process
  if (knownSymbolsArr.indexOf(el.symbol) === -1) {
    // Sum balances when symbol is el.symbol
    const balance = degroupedArr.reduce((acc, val) => val.symbol === el.symbol ? acc + val.balance : acc, 0);
    
    // Add symbol in our knownSymbolsArr
    knownSymbolsArr.push(el.symbol);
    
    // Add data in our final array
    finalArr.push({
      symbol: el.symbol,
      balance: balance
    });
  }
});

console.log(finalArr);

Answer 2

解决方案可以分为两部分：

展平输入数组
将展平数组的元素按symbol分组并计算总和。

const ar = [
  [{symbol: "xy", balance: 2155113}, {symbol: "asda", balance: 21231231}],
  [{symbol: "asda", balance: 6543}, {symbol: "xy", balance: 21678}]
]

const flattenedAr = ar.reduce((acc, curElement) => {
  acc = [...acc, ...curElement];
  return acc;
}, []);

const groupedAr = flattenedAr.reduce((group, curElement) => {

  const matchingElement = group.find(ele => ele.symbol === curElement.symbol);
  if(matchingElement) {
   matchingElement.summedBalance += curElement.balance;
  } else { 
   group.push({
     symbol: curElement.symbol,
     summedBalance: curElement.balance
   }); 
  }
   
  return group
}, [])

console.log(groupedAr)

用节点分组 / Javascript

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