枢轴或转换JavaScript对象 [英] Pivot or Transforming JavaScript object

问题描述

我有以下JavaScript对象.我需要从给定的对象生成一个新的对象.我应该使用JavaScript采取什么方法?

I have the following JavaScript object. I need to generate a new object from the given object. What is the approach I should take in JavaScript?

[
 {"name": "Dan",  "city" : "Columbus", "ZIP":"47201"},
 {"name": "Jen",  "city" : "Columbus", "ZIP":"47201"},
 {"name": "Mark", "city" : "Tampa",  "ZIP":"33602"},
]

如何转换或旋转以生成以下对象?

How can I transform or pivot to generate the following object?

[
 { "47201": [
              {"name": "Dan", "city": "Columbus"},
              {"name": "Jen", "city": "Columbus"},
             ],
    "count": "2"
  },
  { "33602": [
              {"name": "Mark", "city": "Tampa"}
             ],
    "count": "1"
  }
 ]

推荐答案

我不知道为什么要使用.count属性，但是可以通过数组的.length属性进行访问，但是无论如何:

I don't know why you want the .count property, when that can be accessed via the array's .length property, but anyway:

const input = [
  {"name": "Dan",  "city" : "Columbus", "ZIP":"47201"},
  {"name": "Jen",  "city" : "Columbus", "ZIP":"47201"},
  {"name": "Mark", "city" : "Tampa",  "ZIP":"33602"},
]

const working = input.reduce((acc, {ZIP, name, city}) => {
  (acc[ZIP] || (acc[ZIP] = [])).push({name, city})
  return acc
}, {})

const output = Object.keys(working)
  .map(k => ({[k]: working[k], count: working[k].length}))

console.log(output)

进一步阅读:

• 数组.reduce()
• 数组.map()
• Object.keys()
• 从作为函数参数传递的对象中解压缩字段
• 计算出的属性名称

• Array .reduce()
• Array .map()
• Object.keys()
• Unpacking fields from objects passed as function parameters
• Computed property names

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