How to Join Map In Golang (Map Union)

golang_reduce_map.go

package main

import (
	"fmt"
)

type Item struct{
	Id int
	Name string
	Qty int
}

type Maps map[int]Item

func ReduceItem(m1, m2 Maps) Maps {
	for ia, va := range m1 {
		if it, ok := m2[ia]; ok {
			va.Qty += it.Qty
		} 
		m2[ia] = va
				
	}
	return m2
}

func main() {
	m1 := Maps{3: {3, "Wury", 1,}, 5: {5, "Sam", 1,}} 
	m2 := Maps{1: {1, "Alex", 1,}, 2: {2, "Ben", 1, }, 3: {3, "Wury", 1,}, 4: {4, "Lara", 2,}}
	r := ReduceItem(m2, m1)
	fmt.Println(r)
	
	
}