Question

我有两个数组：

initial=[{code:"1",size: 0},{code:"2",size: 0},{code:"3",size: 0},{code:"4",size: 0}];
update=[{code:"1",size: 100},{code:"2",size: 100},{code:"2",size: 120}];

我需要得到这样的新数组：

我想按代码字段进行分组，并在分组后进行尺寸总和。

new=[{code:"1",size: 100},{code:"2",size: 220},{code:"3",size: 0},{code:"4",size: 0}];

Answer 1

您可以使用具有相同代码的对象的哈希表。

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var initial = [{ code: "1", size: 0 }, { code: "2", size: 0 }, { code: "3", size: 0 }, { code: "4", size: 0 }],
    update = [{ code: "1", size: 100 }, { code: "2", size: 100 }, { code: "2", size: 120 }],
    hash = Object.create(null),
    result = initial.map(function (o) {
        return hash[o.code] = { code: o.code, size: 0 };
    });

update.forEach(function (o) {
    hash[o.code].size += o.size;
});

console.log(result);

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Answer 2

检查一下 https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign

var o1 = { a: 1, b: 1, c: 1 };
var o2 = { b: 2, c: 2 };
var o3 = { c: 3 };

var obj = Object.assign({}, o1, o2, o3);
console.log(obj); // { a: 1, b: 2, c: 3 }

Answer 3

您可以使用.map()的{{1}}，.filter()和.reduce()方法

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Array.prototype

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Answer 4

以下是函数式编程样式中使用ES6 Map的版本：

function addObjects(acc, add) {
    return Array.from(
        add.reduce((mp, {code, size}) => mp.set(code, mp.get(code) + size),
                new Map(acc.map(({code, size}) => [code, size]))),
        ([code, size]) => ({code, size})
    );
} 

const initial = [{ code: "1", size: 0 }, { code: "2", size: 0 }, { code: "3", size: 0 }, { code: "4", size: 0 }],
      update = [{ code: "1", size: 100 }, { code: "2", size: 100 }, { code: "2", size: 120 }];

const res = addObjects(initial, update);

console.log(res);

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Answer 5

您可以使用array#concat加入数组，然后使用array#reduce汇总对象内的大小，然后从该对象中获取值。

＆＃13;

const initial=[{code:"1",size: 0},{code:"2",size: 0},{code:"3",size: 0},{code:"4",size: 0}],
      update=[{code:"1",size: 100},{code:"2",size: 100},{code:"2",size: 120}];

let result = initial
              .concat(update)
              .reduce((res, {code, size}) => {
                res[code] = {code, size : (res[code]|| {size:0}).size + size};
                return res;
              },Object.create(null));

let output = Object.values(result);
console.log(output);

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如何根据另一个对象数组更新对象数组

5 个答案: