How to convert string to JSON in Go? - json

Question

Let’s say I have this string:
`
{
"testCode": 0,
"replyTest": "OK",
"data": {
"001": {
"fields": {
"name": "arben",
"fav_color": "blue",
"address": "PH",
}
},
"002": {
"fields": {
"name": "john",
"fav_color": "black",
"address": "PH",
}
},
}
}
`
How to convert this string to JSON where data is in form of list in order for me to loop this list in a process?

Answer 1

Whenever you have json property names that aren't known upfront, or they don't lend themselves very well to be represented as fields of a struct then you're left more or less with one option, a map. So first you need to unmarshal the "data" property into a map.
However maps in Go are implemented as unordered groups of elements indexed by a set of unique keys. So basically there's no way to ensure the order of a map in Go, and therefore you'll have to transfer the data from the map into something that can be ordered, like a slice for example.
After you've got your data in the slice you can use the standard sort package to sort the slice in the order you want.
You can start by declaring the types you need:
type DataItem struct {
Key string `json:"-"`
Fields DataFields `json:"fields"`
}
type DataFields struct {
Name string `json:"name"`
FavColor string `json:"fav_color"`
Address string `json:"address"`
}
Then unmarshal the json
var obj struct {
TestCode int `json:"testCode"`
ReplyTest string `json:"replyTest"`
Data map[string]*DataItem `json:"data"`
}
if err := json.Unmarshal(data, &obj); err != nil {
panic(err)
}
Transfer the contents of the map into a slice
items := []*DataItem{}
for key, item := range obj.Data {
item.Key = key // keep track of the key because it will be used to order the contents of the slice
items = append(items, item)
}
Finally sort the slice
sort.Slice(items, func(i, j int) bool {
return items[i].Key < items[j].Key
})
https://play.golang.com/p/D2u46veOQwD