【问题标题】:React object values undefined whereas the object value is present在对象值存在时反应对象值未定义
【发布时间】:2020-04-16 15:58:40
【问题描述】:

我有一个问题,我有一个这样的对象列表:

(0)
id: 1
service_name: "ETHYLENE OXIDE STERILIZATION"
service_description: "ETHYLENE OXIDE STERILIZATION Ethylene oxide (EO) is the leading technology. "

(1)

id: 2
service_name: "ETHYLENE STERILIZATION"
service_description: "ETHYLENE OXIDE is good material. "

上面是对象列表。表示两个对象的列表。现在我想在每个对象中添加一个新键,即图像键。我已经完成了:

 for (let i=0;i<mydata.length;i++){

        axios.get(api_url)
        .then(res=>{

          for (let it=0;it<res.data.length;it++){
            mylist[it]=res.data[0].service_image
          }

          Object.assign(mydata[i],{"images":mylist}) // making a new key in each object

          mylist=[]

        })

当我添加新密钥后打印时:

id: 1
service_name: "ETHYLENE OXIDE STERILIZATION"
service_description: "ETHYLENE OXIDE STERILIZATION Ethylene oxide (EO) is the leading technology. "
images:['url1','url2']

(1)

id: 2
service_name: "ETHYLENE STERILIZATION"
service_description: "ETHYLENE OXIDE is good material"
images:['url3','url4']

我已经成功地将新的关键图像添加到对象 mydata 列表中。但是当我通过 console.log(mydata.images) 访问图像属性时,它给了我未定义但它存在,当我打印 console.log(mydata) 时它打印整个列表我也可以看到图像属性。

我不知道问题是什么,有人可以建议我

【问题讨论】:

    标签: javascript reactjs ecmascript-6 javascript-objects


    【解决方案1】:

    mydata 是一个数组,您的图片位于:

    mydata[0].images
    mydata[1].images
    

    【讨论】:

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