Snippet on how to guess types of data from arbitrary JSON

random_type.go

package main

import (
	"encoding/json"
	"fmt"
	"log"
)

type Hole struct {
	Alias string                 `json:"alias"`
	Id    int                    `json:"id"`
	Data  map[string]interface{} `json:"json_data"`
}

var j = []byte(`{
		"alias": "evergreen-9999",
		"id": 1,
		"json_data": {
			"field_1": "data_1",
			"field_2": 690,
			"field_3": [0, "dada", 8.5, {"key": "val"}],
			"field_4": {"foo": {"bar": "baz"}}
			}
		}`)

func main() {

	var hole Hole
	if err := json.Unmarshal(j, &hole); err != nil {
		log.Fatal("error:", err)
	}

	p := hole.Data

	for k, v := range p {
		switch val := v.(type) {

		case string:
			fmt.Println(k, v, "is a JSON string")

		case float64:
			fmt.Println(k, v, "is a JSON number/float")

		case bool:
			fmt.Println(k, v, "is a JSON Boolean")

		case []interface{}:
			fmt.Println(k, v, "is a JSON array")
			for i, v := range val {
				fmt.Println(i, v)
			}
		case map[string]interface{}:
			fmt.Println(k, v, "is a JSON Value")
			fmt.Println(v)
			/*
				for _k, _v := range v.(map[string]interface{}) {
					switch _val := _v.(type) {
					case string:
						fmt.Println(_k, _v, "STRING")
					case float64:
						fmt.Println(_k, _v, "NUM")
					case bool:
						fmt.Println(_k, _v, "BOOL")
					}
				}*/

		default:
			fmt.Println(k, "is unknown")
		}
	}
}