first_case.go

package southern_light

import (
	"unicode"
	"unicode/utf8"
)

// https://stackoverflow.com/questions/75988064/make-first-letter-of-string-lower-case-in-golang
func FirstToLower(s string) string {
	r, size := utf8.DecodeRuneInString(s)
	if r == utf8.RuneError && size <= 1 {
		return s
	}
	lc := unicode.ToLower(r)
	if r == lc {
		return s
	}
	return string(lc) + s[size:]
}

func FirstToUpper(s string) string {
	r, size := utf8.DecodeRuneInString(s)
	if r == utf8.RuneError && size <= 1 {
		return s
	}
	lc := unicode.ToUpper(r)
	if r == lc {
		return s
	}
	return string(lc) + s[size:]
}