使用组合键值将 JSON 数组减少为 object

Question

我有一个这样的数组：

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

按照这个问题的答案，我设法做到了这一点：

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/优雅的方式，可能是通过使用其他 JS 函数（例如 reduce、map 等）。 干杯!

Answer 1

如果您非常关心代码性能（效率），那么您会喜欢这个...

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