使用相同的键（javascript）将属性从一个数组添加到另一个数组 [英] Add property from one array into another array with the same key (javascript)

问题描述

您好，而不是用文字解释它我刚刚在下面做了一个快速的视觉表示。

Hello instead of explaining it in words I've just made a quick visual representation below.

说我有以下数组：

let arr1 = [
  {
    id: 1,
    someKey: someValue
  },
  {
    id: 2,
    someKey: someValue
  },
]

和另一个数组：

let arr2 = [
  {
    id: 1,
    numberOfItems: 10
  },
  {
    id: 2,
    numberOfItems: 20
  },
]

我如何创建以下数组？

let result = [
  {
    id: 1,
    someKey: someValue,
    numberOfItems: 10
  },
  {
    id: 2,
    someKey: someValue,
    numberOfItems: 10
  },
]

正如您所看到的，两个数组都具有相同的 id 值。我想从第二个数组中取 numberOfItems：10 并将它放在同一个id下的第一个数组中。

So as you can see, both arrays have the same id value. I want to take numberOfItems: 10 from the second array and place it into the first array under the same id.

注意：两个ID完全不同，具有不同的属性和长度。唯一的相似之处是 id

Note: the two ids are completely different, have different properties and length. The only similarity is the id

谢谢！

推荐答案

您可以先创建一个id为key的地图，然后合并对象这将解决O（n）中的问题：

You could first create a map with id as key and then combine the objects This would solve the problem in O(n):

let arr1 = [
  {
    id: 1,
    someKey: 3
  },
  {
    id: 2,
    someKey: 6
  },
];

let arr2 = [
  {
    id: 1,
    numberOfItems: 10
  },
  {
    id: 2,
    numberOfItems: 20
  },
];

let arr2Map = arr2.reduce((acc, curr) => {
  acc[curr.id] = curr
  return acc;
}, {});
let combined = arr1.map(d => Object.assign(d, arr2Map[d.id]));
console.log(combined);

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