javascript无法映射具有嵌套值的对象数组 [英] javascript cannot map array of objects with nested values

问题描述

尝试映射具有嵌套在子对象结构中的值的对象数组：

Trying to map array of objects with values nested in child objects structure like:

const objs = [{
        "B": {
            "value": 1,
        },
        "D": {
            "value": "45"
        },
        "E": {
            "value": "234"
        },
        "A": {
            "value": "543"
        },
        "C": {
            "value": "250"
        }
    },...]

改为以下结构：

[
  { name: 'B', value: 1 }, 
  { name: 'D', value: '45' }, 
  { name: 'E', value: '234' }, 
  { name: 'A', value: '543' },
  { name: 'C', value: '250' }
]

，并且映射结果为 undefined

const mapped = objs.map((key, index) => {
  Object.keys(key).map(el => ({
    name: el
  }))
})

示例： Stackblitz

推荐答案

您缺少 return 语句和值属性定义。

You are missing return statement and value property definition.

此外，您可能还想使用 flatMap 而不是地图，以避免在结果中嵌套数组：

Besides you may want to use flatMap instead of map in order to avoid a nested array in the result:

const objs = [{
    "B": {
        "value": 1,
    },
    "D": {
        "value": "45"
    },
    "E": {
        "value": "234"
    },
    "A": {
        "value": "543"
    },
    "C": {
        "value": "250"
    }
}]

const mapped = objs.flatMap((key, index) => {
    return Object.keys(key).map(el => ({
        name: el,
        value: key[el].value
    }))
})

console.log(mapped)

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