grokify/mogo

package languageutil

import (
    "fmt"
    "strings"

    "golang.org/x/text/language"
)

var languageConjunctionMap = map[language.Tag]string{
    language.English: "and",
}

func JoinLanguage(slice []string, sep string, joinLang language.Tag) (string, error) {
    switch len(slice) {
    case 0:
        return "", nil
    case 1:
        return slice[0], nil
    case 2:
        if joinWord, ok := languageConjunctionMap[joinLang]; ok {
            return slice[0] + " " + joinWord + " " + slice[1], nil
        }
        return strings.Join(slice, sep), fmt.Errorf("join word not found for language [%v]", joinLang)
    default:
        last, rest := slice[len(slice)-1], slice[:len(slice)-1]
        if joinWord, ok := languageConjunctionMap[joinLang]; ok {
            rest = append(rest, joinWord+" "+last)
            return strings.Join(rest, sep+" "), nil
        }
        return strings.Join(slice, sep), fmt.Errorf("join word not found for language [%v]", joinLang)
    }
}