Javascript：折叠属性值上的对象数组，求和数量属性，保留最近的

Question

寻找更实用的“功能”方式......我有一个产品的对象看起来像这样（注意重复skuid的）"products": [     {       "skuid": "B1418",       "name": "Test Product 1",       "price": 7,       "lastOrderedDate": 20181114,       "quantity": 2     },{       "skuid": "B3446",       "name": "Test Product 2",       "price": 6,       "lastOrderedDate": 20190114,       "quantity": 2     },{       "skuid": "B1418",       "name": "Test Product 1",       "price": 7,       "lastOrderedDate": 20180516,       "quantity": 5     },{       "skuid": "B3446",       "name": "Test Product 2",       "price": 6,       "lastOrderedDate": 20180411,       "quantity": 11     }]我想创建一个新的数组，每个不同的单个对象，skuid但SUMS所有的quantity值，并保留最新的lastOrderedDate。最终结果如下："products": [     {       "skuid": "B1418",       "name": "Test Product 1",       "price": 7,       "lastOrderedDate": 20181114,       "quantity": 7     },{       "skuid": "B3446",       "name": "Test Product 2",       "price": 6,       "lastOrderedDate": 20190114,       "quantity": 13     }]我可以用一堆forEach和if来做，但我想学习一种更简洁的方法来做到这一点。或许有一种，那么reduce？

Answer 1

您可以Map稍后获取并获取所有值作为结果集。

const

    getGrouped = (m, o) => {

        var item = m.get(o.skuid);

        if (!item) return m.set(o.skuid, Object.assign({}, o));

        if (item.lastOrderedDate < o.lastOrderedDate) item.lastOrderedDate = o.lastOrderedDate;

        item.quantity += o.quantity;

        return m;

    };

var data = { products: [{ skuid: "B1418", name: "Test Product 1", price: 7, lastOrderedDate: 20181114, quantity: 2 }, { skuid: "B3446", name: "Test Product 2", price: 6, lastOrderedDate: 20190114, quantity: 2 }, { skuid: "B1418", name: "Test Product 1", price: 7, lastOrderedDate: 20180516, quantity: 5 }, { skuid: "B3446", name: "Test Product 2", price: 6, lastOrderedDate: 20180411, quantity: 11 }] },

    result = Array.from(data.products

        .reduce(getGrouped, new Map)

        .values()

    );

console.log(result);

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