将 JSON 数组减少为具有组合键值的对象

如何解决将 JSON 数组减少为具有组合键值的对象

我有一个这样的数组：

[
    { "avl_res": 1,"res_status": "Available","code": "AAA" },{ "avl_res": 2,"res_status": "Unavailable","code": "BBB" },{ "avl_res": 1,"code": "CCC" },{ "avl_res": 5,{ "avl_res": 3,"code": "DDD" },];

我正在尝试制作这个：

[
    {"avl_res":1,"total_res":3,"code":"AAA"},{"avl_res":2,"total_res":2,"code":"BBB"},{"avl_res":1,"total_res":6,"code":"CCC"},{"avl_res":0,"code":"DDD"},];

根据对 question 的回答，我设法做到了：

var singles = {};
arr.forEach(function (item) {
    var single = singles[item.code] = singles[item.code] || {};
    single[item.res_status] = item.avl_res;
});

var outputList = [];
for (var single in singles) {
    let total_res = 0;
    let avl_res = 0;

    singles[single]['Available'] ? avl_res = singles[single]['Available'] : avl_res = 0;
    singles[single]['Unavailable'] ? total_res = avl_res + singles[single]['Unavailable'] : total_res = avl_res;

    outputList.push({ code: single,total_res: total_res,avl_res: avl_res });
}

console.log(outputList);

只是想知道这是否足够有效，或者有更好/更优雅的方式，也许是通过使用其他 JS 函数（例如，reduce、map 等）。干杯！

解决方法

如果你那么关心代码性能（效率），你会喜欢这个...

const arr = [
    { "avl_res": 1,"res_status": "Available","code": "AAA" },{ "avl_res": 2,"res_status": "Unavailable","code": "BBB" },{ "avl_res": 1,"code": "CCC" },{ "avl_res": 5,{ "avl_res": 3,"code": "DDD" },];

const results = [];
const findItem = {};

for (const { avl_res,code,res_status } of arr) {
    let item = findItem[code];
    const res = res_status == 'Available' ? avl_res : 0;
    if (item) {
        item.total_res += avl_res;
        item.avl_res += res;
    }
    else {
        item = { avl_res: res,total_res: avl_res,code };
        results.push(item);
        findItem[code] = item;
    }
}
console.log(results);