mapToStruct.go

package main

import (
	"encoding/json"
	"fmt"
	"reflect"
	"testing"
)

type Person struct {
	Name string
	Age  string
}

func MapToStruct[T any](m map[string]string, s *T) error {
	structValue := reflect.ValueOf(s).Elem()

	for k, v := range m {
		structFieldValue := structValue.FieldByName(k)

		if !structFieldValue.IsValid() {
			return fmt.Errorf("no such field: %s in obj", k)
		}

		if !structFieldValue.CanSet() {
			return fmt.Errorf("cannot set %s field value", k)
		}

		fieldValueT := reflect.ValueOf(v)
		if structFieldValue.Type() != fieldValueT.Type() {
			return fmt.Errorf("provided value type didn't match obj field type")
		}

		structFieldValue.Set(fieldValueT)
	}

	return nil
}

func BenchmarkJSONMapToStruct(b *testing.B) {
	m := map[string]string{
		"Name": "Alice",
		"Age":  "30",
	}

	for i := 0; i < b.N; i++ {
		var p Person
		jsonData, err := json.Marshal(m)
		if err != nil {
			b.Error(err)
		}

		err = json.Unmarshal(jsonData, &p)
		if err != nil {
			b.Error(err)
		}
	}
}

func BenchmarkReflectMapToStruct(b *testing.B) {
	m := map[string]string{
		"Name": "Alice",
		"Age":  "30",
	}

	for i := 0; i < b.N; i++ {
		var p Person
		err := MapToStruct(m, &p)
		if err != nil {
			b.Error(err)
		}

	}
}

Results.md

Benchmark Results

goos: windows
goarch: amd64
pkg: go-struct-benchmarks
cpu: AMD Ryzen Threadripper 3960X 24-Core Processor 

Benchmark	Iterations	Time/Iteration	Memory/Iteration	Allocs/Iteration
BenchmarkJSONMapToStruct-48	655564	1702 ns/op	617 B/op	16 allocs/op
BenchmarkReflectMapToStruct-48	3228502	376.7 ns/op	80 B/op	5 allocs/op