如何将所有解码的数据写入JSON文件？

I try to parse an XML data to a JSON file, but when I begin writing marshaled data to a JSON, it just rewrites data in the JSON file and, as a result, I have the file with last XML element. How to write the whole data into the JSON file?

Snippet of code that parses XML and marshal data to JSON

    decoder := xml.NewDecoder(file)
    resultData := map[string]map[string]string{}
    for {
        t, _ := decoder.Token()
        if t == nil {
            break
        }

        switch et := t.(type) {
        case xml.StartElement:
            if et.Name.Local == "profile" {
                var object XMLProfile
                decoder.DecodeElement(&object, &et)

                resultData = map[string]map[string]string{
                    object.ProfileName: {},
                }

                for _, val := range object.Fields {
                    resultData[object.ProfileName][val.Name] = val.Value
                }
            }
        }
    }

    if out, err := json.MarshalIndent(resultData, "", "\t"); err != nil {
        panic(err)
    } else {
        _ = ioutil.WriteFile("test.json", out, 0644)
    }

Expect JSON:

{
  "Profile 1": {
      "role": "user"
  },

  "Profile 2": {
      "role": "user"
  },

  "Profile 3": {
      "role": "admin"
  }
}

Actual JSON:

{
  "Profile 3": {
    "role": "admin"
  }
}