需要帮助从 JavaScript 中的对象数组中获取计数

Question

我正在处理一组看起来像这样的对象：

const fruits = [
 {
   Fruit: Apple,
   Count: 4
 },
 {
   Fruit: Orange,
   Count: 3
 },
 {
   Fruit: Apple,
   Count: 2
 }
]

我希望我的数组看起来像这样：

const fruits = [
 {
  Fruit: Apple,
  Count: 6
 },
 {
  Fruit: Orange,
  Count: 3
 },
]

有什么帮助吗？我曾尝试使用 Reduce，但不用说，Reduce 是我在 JavaScript 中最大的弱点。我看了很多文章，得到了接近的答案，但没有什么能完全帮助我。感谢您的帮助。

Answer 1

这是您需要的 reduce 解决方案：

const fruits = [
 {
   Fruit: "Apple",
   Count: 4
 },
 {
   Fruit: "Orange",
   Count: 3
 },
 {
   Fruit: "Apple",
   Count: 2
 }
]

let result = fruits.reduce((acc,current) => {
   let obj = acc.find(x => x.Fruit === current.Fruit);
   if(!obj){
      acc.push({ Fruit: current.Fruit, Count: current.Count });
   } else {
      obj.Count += current.Count;
   }
   return acc;
}, []);

console.log(result);

基本上您需要构建一个新数组 (acc) 并在没有这样的项时添加一个新项 Fruit 或增加计数器。

Answer 2

const fruits = [{
    Fruit: "Apple",
    Count: 4
  },
  {
    Fruit: "Orange",
    Count: 3
  },
  {
    Fruit: "Apple",
    Count: 2
  }
];

// c => current value
// n => next value
const asObject = fruits.reduce((c, n) => ({ ...c,
  [n.Fruit]: (c[n.Fruit] || 0) + n.Count
}), {});

const result = Object.entries(asObject).map(([k, v]) => ({
  Fruit: k,
  Count: v
}));

console.log(asObject);
console.log(result);

需要帮助从 JavaScript 中的对象数组中获取计数

Need helping in getting counts out of an array of objects in JavaScript

javascript

sorting

reduce

object