从具有多个属性的数组映射 json 数据答案

【问题标题】：Map json data from array with several properties从具有多个属性的数组映射 json 数据
【发布时间】：2020-10-05 20:18:32
【问题描述】：

我有以下 json 对象

https://codebeautify.org/jsonviewer/cb01bb4d

obj = 
{
  "api": "1.0.0",
  "info": {
    "title": "Events",
    "version": "v1",
    "description": "Set of events"
  },
  "topics": {
    "cust.created.v1": {                            //Take this value
      "subscribe": {
        "summary": "Customer Register Event v2",    //Take this value
        "payload": {
          "type": "object",
          "required": [
            "storeUid"

          ],
          "properties": {
            "customerUid": {
              "type": "string",
              "description": "Email of a Customer",
              "title": "Customer uid"
            }
          }
        }
      }
    },
    "qu.orderplaced.v1": {                     //Take this value
      "subscribe": {
        "summary": "Order Placed",             //Take this value
        "payload": {
          "type": "object",
          "required": [
            "quoteCode"
          ],
          "properties": {
            "quoteCode": {
              "type": "string",
              "example": "762",
              "title": "Quote Code"
            }
          }
        }
      }
    } 
  }
}

我需要将 json 对象的值映射到 javascript 数组

例如：

MyArray = [
 {
   Label: “cust.created.v1”,
   Description:  "Customer Register Event v2"

 },
 {
   Label: “qu.orderplaced.v1”,
   Description: "Order Placed",
 }
]

我需要映射两个值，每个实例的 key => label（例如“cust.created.v1”）和 summary => Description 来自每个实例

我尝试用map 来做，但我很难用 key 和里面的属性来做，可以用 map 做吗？

【问题讨论】：

标签： javascript node.js json typescript lodash

【解决方案1】：

获取对象的entries 然后映射它：

var obj = { "api": "1.0.0", "info": { "title": "Events", "version": "v1", "description": "Set of events" }, "topics": { "cust.created.v1": { "subscribe": { "summary": "Customer Register Event v2", "payload": { "type": "object", "required": [ "storeUid" ], "properties": { "customerUid": { "type": "string", "description": "Email of a Customer", "title": "Customer uid" } } } } }, "qu.orderplaced.v1": { "subscribe": { "summary": "Order Placed", "payload": { "type": "object", "required": [ "quoteCode" ], "properties": { "quoteCode": { "type": "string", "example": "762", "title": "Quote Code" } } } } }}}

var result = Object.entries(obj.topics).map(([k,v])=>({Label:k, Description:v.subscribe.summary}));

console.log(result);

【讨论】：

谢谢，我在 TS 中运行它，我收到以下错误：Object is of type 'unknown'.ts(2571) 对于这个 v.subscribe.summary ，知道如何克服这个问题吗？
@BenoOdr 将 map(([k,v] as any) 替换为 map(([k,v])。它应该可以工作
我像var result = Object.entries(obj.topics).map(([k,v] as any )=>({Label:k, Description:v.subscribe.summary})); 一样尝试过，但我得到了编译错误，我错过了什么吗？
像var result = Object.entries(obj.topics).map(([k,v]: any )=>({Label:k, Description:v.subscribe.summary}));一样修复它，你知道如果我想为TS使用显式类型，我应该如何使用它？

【解决方案2】：

Object.entries 是问题的关键；）

Object.entries(obj.topics).map(topic => ({
    Label: topic[0],
    Description: topic[1].subscribe.summary
}))

如果您不确定是否为 topic[1].subscribe，您可以使用 topic[1].subscribe?.summary 或 topic[1].subscribe && topic[1].subscribe.summary 来掩护您

你也可以解构 Object.entries 的内部数组，可能会更简洁一些

const obj = { "api": "1.0.0", "info": { "title": "Events", "version": "v1", "description": "Set of events" }, "topics": { "cust.created.v1": { "subscribe": { "summary": "Customer Register Event v2", "payload": { "type": "object", "required": [ "storeUid" ], "properties": { "customerUid": { "type": "string", "description": "Email of a Customer", "title": "Customer uid" } } } } }, "qu.orderplaced.v1": { "subscribe": { "summary": "Order Placed", "payload": { "type": "object", "required": [ "quoteCode" ], "properties": { "quoteCode": { "type": "string", "example": "762", "title": "Quote Code" } } } } }}}

const arr = Object.entries(obj.topics).map(([Label, content]) => ({ 
   Label, 
   Description: content.subscribe?.summary 
}))

console.log(arr)

【讨论】：

哪个错误？ Object.entries 总是返回一个包含 [key, value] 数组的数组。您可以像 gorak 那样解构内部数组来访问它，或者使用 [0] 访问键并使用 [1] 访问值。也许您正在尝试的对象未定义 topic[1].subscribe？

【解决方案3】：

您可以映射主题中的所有键，并且对于每个项目，您可以从该对象中提取任何数据，如下所示：

Object.keys(obj.topics).map((key) => { return {Label: key, Description: obj.topics[key].subscribe.summary} })

【讨论】：

【解决方案4】：

你可以这样做

let obj = { "api": "1.0.0", "info": { "title": "Events", "version": "v1", "description": "Set of events" }, "topics": { "cust.created.v1": { "subscribe": { "summary": "Customer Register Event v2", "payload": { "type": "object", "required": [ "storeUid" ], "properties": { "customerUid": { "type": "string", "description": "Email of a Customer", "title": "Customer uid" } } } } }, "qu.orderplaced.v1": { "subscribe": { "summary": "Order Placed", "payload": { "type": "object", "required": [ "quoteCode" ], "properties": { "quoteCode": { "type": "string", "example": "762", "title": "Quote Code" } } } } }}}


let outputArray = Object.keys(obj.topics).map((key)=>(
    { Label: key, Description: obj.topics[key]['subscribe']['summary'] }
))

console.log(outputArray)

【讨论】：