从具有多个属性的数组映射 json 数据

Posted 2023-03-07

【中文标题】从具有多个属性的数组映射 json 数据

【英文标题】：Map json data from array with several properties

【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？

【参考方案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？

【参考方案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？

【参考方案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 )

【参考方案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)