Escaping @everyone in Go

strip.go

// EscapeEveryone escapes @everyone and @here mentions.
func EscapeEveryone(s string) string {
    var mentionBuf string
    var mentionInd int

    for i, r := range s {
        if r == '@' && i != len(s)-1 {
            mentionBuf += string(r)
            mentionInd = i
            continue
        }

        if unicode.IsSpace(r) {
            mentionBuf = ""
            continue
        }

        if mentionBuf != "" && unicode.IsLetter(r) {
            mentionBuf += string(r)
        }

        if stringsCmp(mentionBuf, "@everyone", "@here") {
            s = s[:mentionInd+1] + "\u200b" + s[mentionInd+1:]

            // Reset buffer
            mentionBuf = ""
            mentionInd = 0
        }
    }

    return s
}

func stringsCmp(str string, cmp ...string) bool {
	for _, c := range cmp {
		if c == str {
			return true
		}
	}

	return false
}

strip_test.go

func TestEscapeEveryone(t *testing.T) {
    var samples = [...]string{
        "@everyone",
        "@\u202eeveryone",
    }

    for _, sample := range samples {
        esc := EscapeEveryone(sample)
        if !strings.HasPrefix(esc, "@\u200b") {
            t.Fatal("Escape failed:", fmt.Sprintf("%#v", esc))
        }
    }
}