Hi, gophers. Just started learning go, could you please tell me is it a good variation of custom append implementation?

Getting Help Code Review
1

func customApend(slice int, val …int)int {
var reslen int = len(slice) + len(val)
var res int
var rescap = 1
if cap(slice) < reslen + len(val){
rescap = (len(slice) + len(val)) * 2
}else {
rescap = cap(slice)
}
res = make(int, reslen, rescap)
copy(res,slice)
var index = len(slice)
for _,v := range val {
res[index] = v
index +=1
}

return res
}

2

You can take advantage of append

func customApend(slice int, val …int) int {
res := make(int, 0, len(slice)+len(val))
res = append(res, slice…)
res = append(res, val…)

return res
}