Question

我已经尝试了xy，x ['y']，xyz，x ['y']。z的每个组合，我能想到的，但我不能为我的生活中访问对象值的值键名称的数组。以下是从SQL查询返回的内容：

parseMissionData:  {record: Array(1), code: 1}
    code: 1
    record: Array(1)
        0: alt: 45
        attribute: Array(6)
            0: {name: "messageCode", value: "10"}
            1: {name: "gpsFix", value: "2"}
            2: {name: "autonomous", value: "0"}
            3: {name: "lowBattery", value: "1"}
            4: {name: "intervalChange", value: "30"}
            5: {name: "resetDetected", value: "0"}
            length: 6
        __proto__: Array(0)
        azimuth: 0
        datetime: "2018-03-24T20:10:00.000Z"
        devid: "300434060496300"
        lat: 37.335394620895386
        lon: -121.82005405426025
        speed: 0
        __proto__: Object
            length: 1
        __proto__: Array(0)
        __proto__: Object
....

我无法保证属性将始终以相同的顺序返回，因此我不能假设属性[0]将始终是messageCode属性。我正在尝试测试的值是messageCode属性，所以我可以键入它的值。我试过了

response.record[i].attribute['messageCode']
response.record[i].attribute.message.value
response.record[i].attribute['messageCode'].value

以及其他一些排列。有没有办法直接访问名为'messageCode'的属性，或者我是否必须遍历数组属性并寻找与名称值的匹配？

更新。我尝试过Mathias247的建议，现在代码如下：

          function parseMissionData( response ) {
            console.log('parseMissionData: ', response);
            var codeAttribute;
            for ( var i=0; i < response.record.length; i++ )
              codeAttribute = response.record[i].attribute.find(elem => elem.name == "messageCode");
              console.log('messageCode: ', codeAttribute );
              //console.log('codeAttribute: ', codeAttribute);
              //console.log('imei via find: ', response.record[i].find(elem => elem.name == "devid"))
              console.log('imei direct: ', response.record[i].devid);
          }

使用更新的代码，我现在可以看到messageCode的值，就像我希望的那样。但奇怪的是现在我对imei（response.record [i] .devid）的引用被打破并返回一个未定义的！如果我为messageCode注释掉find（elem =＆gt; ...），则response.record [i] .devid引用可以正常工作。我显然不明白如何使用find引用某些内容可能会破坏以前的工作。有人可以帮助理解这里的互通吗？

    messageCode:  {name: "messageCode", value: "10"}
 jquery.min.js:2 jQuery.Deferred exception: Cannot read property 'devid' of undefined TypeError: Cannot read property 'devid' of undefined
     at parseMissionData (http://localhost:3000/js/controller.js:1036:67)
     at Object.<anonymous> (http://localhost:3000/js/controller.js:1021:17)
     at j (http://localhost:3000/js/jquery.min.js:2:29948)
     at k (http://localhost:3000/js/jquery.min.js:2:30262) undefined

现在它让我更加困惑。如果我订购这样的控制台日志：

          function parseMissionData( response ) {
            console.log('parseMissionData: ', response);
            var codeAttribute;
            for ( var i=0; i < response.record.length; i++ )
            console.log('imei direct: ', response.record[i].devid);
            codeAttribute = response.record[i].attribute.find(elem => elem.name == "messageCode");
              console.log('messageCode: ', codeAttribute );
              //console.log('codeAttribute: ', codeAttribute);
              //console.log('imei via find: ', response.record[i].find(elem => elem.name == "devid"))
         }

如果我首先记录response.record [i] .imei，它输出正常，但codeAttribute现在记录

jquery.min.js:2 jQuery.Deferred exception: Cannot read property 'attribute' of undefined TypeError: Cannot read property 'attribute' of undefined
    at parseMissionData (http://localhost:3000/js/controller.js:1033:52)
    at Object.<anonymous> (http://localhost:3000/js/controller.js:1021:17)
    at j (http://localhost:3000/js/jquery.min.js:2:29948)
    at k (http://localhost:3000/js/jquery.min.js:2:30262) undefined

如果我颠倒了日志的顺序，属性打印正常，但现在imei记录了一个未定义的错误。我必须做错事，但不能为我的生活找出它是什么。

Answer 1

我是否必须遍历数组属性并查找与名称值匹配的内容？

是的，但您可以使用数组原型函数find轻松查找相关条目。 E.g。

let codeAttribute = response.record[i].attribute.find(elem => elem.name == "messageCode")
// codeAttribute.value === '10'

Answer 2

我尝试重新创建ypur问题，如下所示，并且能够获得＆＃34; messageCode＆＃34;和＆＃34; devid＆＃34;。你能告诉我究竟是什么原因引起你的问题：

a= {name: "messageCode", value: "10"}
b ={name: "gpsFix", value: "2"}
c = {name: "autonomous", value: "0"}
d = {name: "lowBattery", value: "1"}
e = {name: "intervalChange", value: "30"}
f = {name: "resetDetected", value: "0"}


attribute = [a,b,c,d,e,f]



record = { attribute, azimuth: '0', datetime: "2018-03-24T20:10:00.000Z", devid: "300434060496300",lat: '37.335394620895386'}
parseMissionData =  {record, code: 1}

console.log(parseMissionData);

console.log(parseMissionData.record.attribute.find(o => o.name === 'messageCode').value);
console.log(parseMissionData.record.devid)

如何通过键名

2 个答案: