JavaScript 对象结构问题

Question

我在遍历从上传的文件数据返回的对象时遇到问题，但似乎返回的对象结构可能会阻止我从响应中的每个对象捕获特定属性，或者我误解了如何我应该访问这个对象。当我记录 data.length 时，我得到 995，我认为这是对象响应中的字符数。当我记录 data[prop] 时，它会记录每个单独的字符。

这是我返回的文件对象数据:

[
  {
    "fieldname": "fileUpload",
    "originalname": "Screen Shot 2017-01-08 at 12.23.39 PM.png",
    "encoding": "7bit",
    "mimetype": "image/png",
    "size": 39881,
    "bucket": "test",
    "key": "1/2017-01-23/screen-shot-2017-01-08-at-12.23.39-pm.png",
    "acl": "public-read",
    "contentType": "image/png",
    "contentDisposition": null,
    "storageClass": "STANDARD",
    "metadata": null,
    "location": "https://test.s3.amazonaws.com/1/2017-01-23/screen-shot-2017-01-08-at-12.23.39-pm.png",
    "etag": "\"sfasgltg702o\""
  },
  {
    "fieldname": "fileUpload",
    "originalname": "Screen Shot 2017-01-08 at 12.21.04 PM.png",
    "encoding": "7bit",
    "mimetype": "image/png",
    "size": 58386,
    "bucket": "test",
    "key": "1/2017-01-23/screen-shot-2017-01-08-at-12.21.04-pm.png",
    "acl": "public-read",
    "contentType": "image/png",
    "contentDisposition": null,
    "storageClass": "STANDARD",
    "metadata": null,
    "location": "https://test.s3.amazonaws.com/1/2017-01-23/screen-shot-2017-01-08-at-12.21.04-pm.png",
    "etag": "\"151353j53j51u5j135ju\""
  }
]

jQuery AJAX POST 请求上传文件并将对象返回到data:

$.ajax({
            url: '/app/sign',
            type: 'POST',
            data: formData,
            processData: false,
            contentType: false,
            success: function(data){
                console.log('upload successful! ' + data);

                console.log('Just the key ' + data.length);
                for(var prop in data){
                    console.log(data[prop]);
                }
            },
            error: function(error){
                console.log('error ' + JSON.stringify(error));
            }
        });

Answer 1

data 是一个 JSON 字符串，您必须使用 JSON.parse 将其解析回对象数组，如下所示:

success: function(data){
    var arr = JSON.parse(data);

    // use arr as array
    console.log(arr.length);
    // arr[0] is the first object
}