Accessing a nested value in a Go map

I have a random JSON (I will not know the schema ahead of time) that I am marshaling into an map[string]interface{}.
I also have a string representing the field value I would like to return, something like "SomeRootKey.NestValue.AnotherNestValue"

I want to be able to return that value. Is there an simple way to access that value without doing some recursive tricks?

Without recursion? yes, using a loop, but no there's no magical way to do that.

func getKey(m interface{}, key string) (string, bool) {
L:
	for _, k := range strings.Split(key, ".") {
		var v interface{}
		switch m := m.(type) {
		case map[string]interface{}:
			v = m[k]
		case []interface{}:
			idx, err := strconv.Atoi(k)
			if err != nil || idx > len(m) {
				break L
			}
			v = m[idx]
		default:
			break L
		}
		switch v := v.(type) {
		case map[string]interface{}:
			m = v
		case []interface{}:
			m = v
		case string:
			return v, true
		default:
			break L
		}
	}
	return "", false
}

Using json like:

{
	"SomeRootKey": {
		"NestValue": {"AnotherNestValue": "object value"},
		"Array": [{"AnotherNestValue": "array value"}]
	}
}

You can use:

fmt.Println(getKey(m, "SomeRootKey.NestValue.AnotherNestValue"))
fmt.Println(getKey(m, "SomeRootKey.Array.0.AnotherNestValue"))

<kbd>playground</kbd>