JSON 结果 JavaScript 点符号查询 returns 未定义

Question

我在 JavaScript 方面不是最出色的，但我正在学习。我有一个无线传感器和一个正在练习的智能插头。由于某种原因，我无法到达属性 relay_state。我试过 Dot 和 Bracket 但都 return 未定义。我希望它像我下面的函数一样，但我不确定我做错了什么。基本上我只是想让代码从 returned 解析中检索 relay_state 的值数据。感谢反馈！谢谢。

acState = JSON.parse(returnValue).result.responseData;
                
                /*Returned response: 
                {
                  "system": {
                    "get_sysinfo": {
                      "sw_ver": "1.0.0",
                      "hw_ver": "1.0",
                      "type": "IOT.SMARTPLUGSWITCH",
                      "model": "MODELISHERE",
                      "mac": "MACIDISHERE",
                      "dev_name": "SMARTPLUG",
                      "alias": "PLUG ALIAS",
                      "relay_state": 0, //NEED THIS RETURNED
                      "on_time": 0,
                      "active_mode": "none",
                      "feature": "TIM",
                      "updating": 0,
                      "icon_hash": "",
                      "rssi": -53,
                      "led_off": 0,
                      "longitude_i": -LONGDATA,
                      "latitude_i": LATDATA,
                      "hwId": "HWIDISHERE",
                      "fwId": "00000000000000000000000000000000",
                      "deviceId": "DEVICEIDISHERE",
                      "oemId": "OEMIDISHERE",
                      "next_action": {
                        "type": -1
                      },
                      "err_code": 0
                    }
                  }
                }
                */
            
function value(layer, path, value) {
    var i = 0,
        path = path.split('.');

    for (; i < path.length; i++)
        if (value != null && i + 1 === path.length)
            layer[path[i]] = value;
        layer = layer[path[i]];

    return layer;
    console.Log("Relay State: " + value(acState,'system[get_sysinfo[relay_state]]]'));
};
console.Log("Response Data Parsed: " + acState);

Answer 1

你拥有的是一个对象，要访问它你只需要一个点.. :)

var acState = JSON.parse(returnValue).result.responseData;
console.log(acState.system.get_sysinfo.relay_state);

Answer 2

从初始 JSON.parse 返回的响应没有从中创建对象。所以我第二次解析它来创建对象。现在它 returns 0 是状态。

json1=JSON.parse(returnValue).result.responseData; acState=JSON.parse(json1); 

console.Log("Response Data Parsed: " + acState); 
console.Log("Type: "+typeof acState) 
console.Log("Relay State: " + acState.system.get_sysinfo.relay_state);

JSON 结果 JavaScript 点符号查询 returns 未定义

JSON Results JavaScript dot notation query returns undefined

javascript

parsing

json

undefined