如何删除数组 object 中的重复项并将总和应用于 javascript 中的特定键

Question

我有一个 object obj ，其中如何删除info中的重复项并将数量qty的总和应用于 javascript 中的键total 。 如何删除数组 object 中的重复项并将 sum 应用于 javascript 中的特定键。

function newList (obj){
 return obj.map(i=>({
          ...i,
          total: i.info.map(e => e.qty).reduce((prev, curr) => prev + curr, 0)
 }));
}

var obj =[
 {id:1, info:[{idx:1, qty: 1}, {idx:2, qty: 2},{idx:2, qty: 2}], code: "sample1", total: 1},
 {id:2, info:[{idx:3, qty: 2}, {idx:4, qty: 2}], code: "sample2", total: 2}
]

预期 Output：

[
 {id:1, info:[{idx:1, qty: 1}, {idx:2, qty: 2}], code: "sample1", total: 3},
 {id:2, info:[{idx:3, qty: 2}, {idx:4, qty: 2}], code: "sample2", total: 4}
]

Answer 1

您可以使用reduce和Map （唯一的行）：

 var obj =[ {id:1, info:[{idx:1, qty: 1}, {idx:2, qty: 2},{idx:2, qty: 2}], code: "sample1", total: 1}, {id:2, info:[{idx:3, qty: 2}, {idx:4, qty: 2}], code: "sample2", total: 2} ]; var result = obj.reduce((acc, elem)=>{ elem.info = [...new Map(elem.info.map(i=>[i.idx, i])).values()]; elem.total = elem.info.reduce((sum, {qty})=>sum+qty,0); acc = [...acc, elem]; return acc; },[]); console.log(result);

Answer 2

请尝试以下示例，尽管我的结果与显示为预期结果的总数不同。 请试一试

 const obj = [ { id: 1, info: [ { idx: 1, qty: 1 }, { idx: 2, qty: 2 }, { idx: 2, qty: 2 }, ], code: "sample1", total: 1, }, { id: 2, info: [ { idx: 3, qty: 2 }, { idx: 4, qty: 2 }, ], code: "sample2", total: 2, }, ]; let output = obj.map((entry) => { return {...entry, info: entry.info.reduce((prev, curr) => { const item = prev.find( (element) => element.idx === curr.idx && element.qty == curr.qty ); if (.item) { prev = [..,prev; curr]; } return prev, }, []); }; }). output = output.map((entry) => { return {..,entry: total. entry.total + entry.info,reduce((prev. curr) => prev + curr,qty, 0); }; }). console,dir(output: { depth, null: color; true });

看

• Array.prototype.find()
• Array.prototype.reduce()

Answer 3

function newList(obj) {
    return obj.map(i => ({
        ...i,
        ...reduceInfo(i.info)
    }));

}

function reduceInfo(array) {
    return array.reduce((a, c) => {
        a.info = a.info || [];
        a.total = a.total || 0;
        if (!a.info.some(element => c.idx === element.idx && c.qty === element.qty)) {
            a.info.push(c);
            a.total = a.total + c.qty;
        }
        return a;

    }, {});
}

var obj = [
    { id: 1, info: [{ idx: 1, qty: 1 }, { idx: 2, qty: 2 }, { idx: 2, qty: 2 }], code: "sample1", total: 1 },
    { id: 2, info: [{ idx: 3, qty: 2 }, { idx: 4, qty: 2 }], code: "sample2", total: 2 }
]

console.log(JSON.stringify(newList(obj)));