Javascript 过滤对象数组并动态将属性放入新数组

我的意见如下

[
    {
        "metadata": { "id": 1071, "name": "First" },
        "languages": [
            { "name": "Alpha", "details": [ { "city": "usa", "count": 33 } ] },
            { "name": "Beta", "details": [ { "city": "japan", "count": 3 } ] },
        ]
    },
    {
        "metadata": { "id": 1068, "name": "Second" },
        "languages": [
            { "name": "Alpha", "details": [ { "city": "japan", "count": 10 }, { "city": "usa", "count": 20 } ] },
            { "name": "Beta", "details": [ { "city": "japan", "count": 15 }, { "city": "usa", "count": 25 } ] },
        ]
    },
]

这是我必须按语言Alpha过滤的场景.因此，我必须通过Alpha判断第一个对象和过滤器语言，然后将USA和Japan计数到一个新数组中.类似地，循环第二个对象并提取该计数.

最后，我应该得到新数组中的计数序列

output = { japan: [0, 10], usa: [33, 20] } //for filter by Alpha
output = { japan: [3, 15], usa: [0, 25] } //for filter by Beta

我能够通过使用下面的代码实现上述输出.

const filterBy = (data, name) => {
    return data.reduce((p, c) => {
        for (let langObj of c.languages) {
            if (langObj.name === name) {
                const groupedOnCityCount = langObj.details.reduce((x, {city,count}) => ({ ...x, [city]: count }), {});
                p.usa.push(groupedOnCityCount?.usa || 0);
                p.japan.push(groupedOnCityCount?.japan || 0);
            }
        }
        return p;
    }, { japan: [], usa: [] });
}

const A = filterBy(data, 'Alpha');
const B = filterBy(data, 'Beta');

到目前为止，一切都运转良好.如果输入是动态的，问题就会出现.即，我们不知道输出是否只包括japan和usa(不是静态的)

这是我现在期望的动态输入，而不是早期的静态输入.

[
    {
        "metadata": { "id": 1071, "name": "First" },
        "languages": [
            { "name": "Alpha", "details": [ { "city": "usa", "count": 33 }, { "city": "korea", "count": 20 } ] },
            { "name": "Beta", "details": [ { "city": "japan", "count": 3 } ] },
        ]
    },
    {
        "metadata": { "id": 1068, "name": "Second" },
        "languages": [
            { "name": "Alpha", "details": [] },
            { "name": "Beta", "details": [ { "city": "japan", "count": 15 }, { "city": "russia", "count": 77 } ] },
        ]
    },
]

根据上述输入，大约languages个可能包含其他对象中不存在的额外城市.还有一些可能有空的details:[]

对于上述输入，我想要所需的输出

output = { usa: [33, 0] korea: [20, 0 ] } //for filter by Alpha
output = { japan: [3, 15], russia: [0, 77] } //for filter by Beta

有人能告诉我如何动态获取这个吗？