基于条件JS的数组操作

Question

我有以下数组

0: {productid: "001", containersize: "20", ContCount: 10}
1: {productid: "002", containersize: "20", ContCount: 9}
2: {productid: "001", containersize: "40", ContCount: 4}
3: {productid: "001", containersize: "20", ContCount: 20}
4: {productid: "003", containersize: "20", ContCount: 18}
5: {productid: "001", containersize: "40", ContCount: 7}
6: {productid: "003", containersize: "40", ContCount: 25}

基于这个数组，我想创建一个新的数组，如下所示：

0: {productid: "001", containersize20: 30, containersize40: 11, total: 41}
1: {productid: "002", containersize20: 9, containersize40: 0, total: 9}
2: {productid: "003", containersize20: 18, containersize40: 25, total: 43}

基本上，根据产品类型和容器大小20和40来计算所有容器。

我使用了以下代码：

var group_to_values = data.reduce(function (obj, item) {
            obj[item.productid] = obj[item.productid] || [];
            obj[item.productid].push(item.ContCount);
            return obj;
        }, {});

        var groups = Object.keys(group_to_values).map(function (key) {
            return {productid: key, ContCount: group_to_values[key]};
        });

但从现在起我一直在思考如何走得更远。

Answer 1

这是一个完美的适合reduce。迭代结构，构建一个根据您的规范映射到键的结果对象，然后取值数组：

​

const data = [
  {productid: "001", containersize: "20", ContCount: 10},
  {productid: "002", containersize: "20", ContCount: 9},
  {productid: "001", containersize: "40", ContCount: 4},
  {productid: "001", containersize: "20", ContCount: 20},
  {productid: "003", containersize: "20", ContCount: 18},
  {productid: "001", containersize: "40", ContCount: 7},
  {productid: "003", containersize: "40", ContCount: 25}
];

const res = Object.values(data.reduce((a, e) => {
  if (!(e.productid in a)) {
    a[e.productid] = {
      productid: e.productid, 
      containersize20: 0,
      containersize40: 0,
      total: 0
    };
  }
  
  a[e.productid].containersize20 += e.containersize === "20" ? e.ContCount : 0;
  a[e.productid].containersize40 += e.containersize === "40" ? e.ContCount : 0;
  a[e.productid].total += e.ContCount;
  return a;
}, {}));

console.log(res);

​

Answer 2

您在正确的轨道上，但您可以在单个.reduce中将其实现为一个由productid索引的对象，然后您可以获取该对象的值以将其再次转换为一个数组。不要忘记将containersize字符串转换为一个数字，这样您就可以正确地添加：

​

const input = [
  {productid: "001", containersize: "20", ContCount: 10},
  {productid: "002", containersize: "20", ContCount: 9},
  {productid: "001", containersize: "40", ContCount: 4},
  {productid: "001", containersize: "20", ContCount: 20},
  {productid: "003", containersize: "20", ContCount: 18},
  {productid: "001", containersize: "40", ContCount: 7},
  {productid: "003", containersize: "40", ContCount: 25}
];
const output = Object.values(input.reduce((a, { productid, containersize, ContCount }) => {
  if (!a[productid]) a[productid] = {
    productid,
    total: 0,
    containersize20: 0,
    containersize40: 0,
  };
  a[productid]['containersize' + containersize] += ContCount;
  a[productid].total += ContCount;
  return a;
}, {}));
console.log(output);

​

请注意，所有这些都不是jQuery，这只是简单的内置Javascript，它通常可以实现与jQuery一样的功能。