Deep Copy Maps in Golang

deep_copy_maps.go

package main

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

func deepCopyMap(src map[string]int, dst map[string]int) error {
	if src == nil {
		return errors.New("src cannot be nil")
	}
	if dst == nil {
		return errors.New("dst cannot be nil")
	}
	jsonStr, err := json.Marshal(src)
	if err != nil {
		return err
	}
	err = json.Unmarshal(jsonStr, &dst)
	if err != nil {
		return err
	}
	return nil
}

func main() {
	scores := map[string]int{"Alice": 90, "Bob": 100}

	// Returns Scores: map[Alice:90 Bob:100]
	fmt.Println("Scores:", scores)
	dstScores := make(map[string]int)
	deepCopyMap(scores, dstScores)
	dstScores["Celine"] = 110

	// Returns Scores: map[Alice:90 Bob:100]
	fmt.Println("Scores:", scores)

	// Returns Dst Scores: map[Alice:90 Bob:100 Celine:110]
	fmt.Println("Dst Scores:", dstScores)
}