dynamic url simple example

main.go

type Formatter func() (string, *url.URL)

func (w *weatherAPI) ForecastURL(date, region string) Formatter {
	return func() (string, *url.URL) {
		u := &url.URL{
			Scheme:      w.Scheme,
			Host:        w.Host,
			Path: 	     w.Endpoints.Forecast.Path,
		}

		rq := u.Query()

		rq.Set("dateKey", date)
		rq.Set("regionKey", region)

		u.RawQuery = rq.Encode()

		return http.MethodGet, u
	}
}