Get nested JSON value dynamically by tail-recursion and type-assertions

getJSONVal.go

package main

import (
	"fmt"
)
func GetStructField(f interface{},path []string) interface{} {

	rangeOver := f.( map[string]interface{})
	counter := 0
	maxLen := len(path)-1

	NESTED: //GOTO *Tail Recursion* more performant by reusing the stack frame

	for key, value := range rangeOver {

		if key == path[counter] {

			next,ok := value.( map[string]interface{} )
	
			if ok {

				rangeOver = next
				counter += 1
				goto NESTED


			} else {

				if key == path[maxLen] {

					return value
				}	
			}
		}
		


	}
	return nil //Key doesnt point to a value but to a map
}

func main() {

	var m = map[string]interface{}{
		"path": map[string]interface{}{
			"test" : "hello",
			"to": map[string]interface{}{
				"variable": 1,
				"some": map[string]interface{}{
						"stuff": ":)",
						},
			},
		},
	}
	
	value := GetStructField(m, []string{"path", "to", "some","stuff"} )
	value2 := GetStructField(m, []string{"path", "to", "variable"} )
	value3 := GetStructField(m, []string{"path", "test"} )

	fmt.Printf("%v %v %v", value, value2,value3)
	
}