如何访问 JSON 文档中的子元素答案

【问题标题】：How can i access sub elements in JSON doc如何访问 JSON 文档中的子元素
【发布时间】：2019-09-06 00:40:35
【问题描述】：

这是我的问题，我正在尝试解析具有多个对象但它们不是数组中的对象形式的对象。我的数据是这样的

{ "Jurisdiction": {
         "Mwd Water Stdby Chg": {
             "Tax Type": "Actual",
             "Tax Amount": "$10"
        },
         "Mosq/Fire Ant Assmt": {
             "Tax Type": "Actual",
             "Tax Amount": "$7"
        },
         "Vector Control Chg": {
             "Tax Type": "Actual",
             "Tax Amount": "$2"
        },
         "Total Of Special Assessments": {
             "Tax Type": "Actual",
             "Tax Amount": "$19"
        }
    }

我实际上正在尝试将其转换为 obj 数组，例如

{ "Jurisdiction":[{
         "Tax Name" : "Mwd Water Stdby Chg",
         "Tax Type": "Actual",
          "Tax Amount": "$10"
        }...]

我尝试了多种方法来访问元素下的税收类型等，但没有成功。

var obj = JSON.parse(result);
var keys = Object.keys(obj.Jurisdiction);

for (var i = 0; i < keys.length; i++) {


  console.log(keys[i]["Tax Type"])
  console.log([keys[i]]["Tax Type"])
}

全部返回未定义

【问题讨论】：

既然keys是obj.Jurisdiction的键，那么很明显你需要使用obj.Jurisdiction[keys[i]]
您可能需要使用嵌套的Object.keys().forEach 并为区域推送元素。您还可以查看 lodash 库中的 .toArray 方法

标签： javascript arrays node.js json object

【解决方案1】：

将map 与Object.entries 一起使用：

const obj = {
  "Jurisdiction": {
    "Mwd Water Stdby Chg": {
      "Tax Type": "Actual",
      "Tax Amount": "$10"
    },
    "Mosq/Fire Ant Assmt": {
      "Tax Type": "Actual",
      "Tax Amount": "$7"
    },
    "Vector Control Chg": {
      "Tax Type": "Actual",
      "Tax Amount": "$2"
    },
    "Total Of Special Assessments": {
      "Tax Type": "Actual",
      "Tax Amount": "$19"
    }
  }
};

obj.Jurisdiction = Object.entries(obj.Jurisdiction).map(([k, v]) => ({ "Tax Name": k, ...v }));

console.log(obj);

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【讨论】：

【解决方案2】：

你应该使用 for in 循环来代替：

var obj = { "Jurisdiction": {
         "Mwd Water Stdby Chg": {
             "Tax Type": "Actual",
             "Tax Amount": "$10"
        },
         "Mosq/Fire Ant Assmt": {
             "Tax Type": "Actual",
             "Tax Amount": "$7"
        },
         "Vector Control Chg": {
             "Tax Type": "Actual",
             "Tax Amount": "$2"
        },
         "Total Of Special Assessments": {
             "Tax Type": "Actual",
             "Tax Amount": "$19"
        }
      }
  }
var jur = obj.Jurisdiction, j;
for(var i in jur){
   j = jur[i];
   console.log(i);
   console.log(j['Tax Type']);
   console.log(j['Tax Amount']);
   console.log('-----------------------------');
}

【讨论】：

【解决方案3】：

您可以使用Object.entires() 和map()

const obj = { "Jurisdiction": {
         "Mwd Water Stdby Chg": {
             "Tax Type": "Actual",
             "Tax Amount": "$10"
        },
         "Mosq/Fire Ant Assmt": {
             "Tax Type": "Actual",
             "Tax Amount": "$7"
        },
         "Vector Control Chg": {
             "Tax Type": "Actual",
             "Tax Amount": "$2"
        },
         "Total Of Special Assessments": {
             "Tax Type": "Actual",
             "Tax Amount": "$19"
        }
    }
}

let res = Object.entries(obj.Jurisdiction).map(x => ({'Tax Name':x[0],...x[1]}));
obj.Jurisdiction = res;

console.log(obj)

【讨论】：