Go: How to Parse HH:MM:SS and HH:MM:SS.ttt

parse_hms.go

func ParseHMS(hms string) (time.Duration, error) {
	fields := strings.Split(strings.TrimSpace(hms), ":")
	var s string
	switch len(fields) {
	case 2:
		s = fields[0] + "m" + fields[1] + "s"
	case 3:
		s = fields[0] + "h" + fields[1] + "m" + fields[2] + "s"
	default:
		return time.Duration(0), fmt.Errorf("parse h:m:s: %s", hms)
	}
	return time.ParseDuration(s)
}