Union of Two Slices in Golang

package main

import (
    "fmt"
)

func UnionTwoSlice(slice1, slice2 []int) []int {
    m := make(map[int]bool)

    for _, item := range slice1 {
        m[item] = true
    }

    for _, item := range slice2 {
        if _, ok := m[item]; !ok {
            slice1 = append(slice1, item)
        }
    }
    return slice1
}

func main() {
    var slice1 = []int{8, 6, 11, 21, 156}
    var slice2 = []int{9, 11, 8, 111, 21, 6, 100}
    fmt.Println(UnionTwoSlice(slice1, slice2))
}    
        

Output

[8 6 11 21 156 9 111 100]