custom date time type for JSON

customDateTime.go

type DateTime time.Time

const iso8601 = "2006-01-02 15:04:05Z07:00"

func (dt DateTime) AsTime() time.Time {
	return time.Time(dt)
}

func (dt DateTime) Format(layout string) string {
	return dt.AsTime().Format(layout)
}

func (dt DateTime) MarshalJSON() ([]byte, error) {
	return []byte(dt.AsTime().Format(iso8601)), nil
}

func (dt *DateTime) UnmarshalJSON(b []byte) error {
	t, err := time.Parse(iso8601, string(b))
	if err != nil {
		return err
	}
	*dt = DateTime(t)
	return nil
}

func (dt DateTime) String() string {
	return dt.AsTime().Format(iso8601)
}