ClojureScript

Question

我正在使用 cemerick/url 为 ajax 请求构造我的 URL。但是，查询的某些参数来自异步本机回调。所以我把所有东西都放在 go 块中，如下所示：

(defn myFn [options]
  (go (let [options (cond-> options
                      ;; the asynchronous call
                      (= (:loc options) "getgeo") (assoc :loc (aget (<! (!geolocation)) "coords")))

            constructing the url
            url (-> "http://example.com"

                    (assoc-in [:query :param]  "a param")

                    ;; How do I not associate those if they don't exist ?
                    ;; I tried something along the lines of this, but it obviously doesn't work.
                    ;; (cond->  (and
                    ;;           (-> options :loc :latitude not-nil?)
                    ;;           (-> options :loc :latitude not-nil?))
                    ;;   (do
                    ;;     ))
                    ;; these will fail if there is no "latitude" or "longitude" in options
                    (assoc-in  [:query :lat] (aget (:loc options) "latitude"))
                    (assoc-in  [:query :lng] (aget (:loc options) "longitude"))

                    ;; url function from https://github.com/cemerick/url
                    (url "/subscribe")
                    str)])))

我希望能够将 {:loc "local} 或 {:loc {:latitude 12 :longitude 34}} 或 {} 作为参数传递给我的函数。我觉得我没有使用正确的结构。

我应该如何构造这个 url ?

Answer 1

如果我没看错你的问题，你需要代码，如下所示：

;; helper function
(defn add-loc-to-url-as [url loc k as-k]
  (if-let [v (k loc)]
    (assoc-in url [:query as-k] v)
    url))

;; define function, that process options and extends URL
(defn add-location [url options]
  (if-let [location (:loc options)]
    (if (string? location)
      ;;; it expects string, for {:loc "San Francisco"}
      (assoc-in url [:query :location] location)
      ;;; or map, for {:loc {:latitude 12.123, :longitude 34.33}}
      (-> url
          (add-loc-to-url-as location :latitude :lat)
          (add-loc-to-url-as location :longitude :lng)))
    url))

;; now you can use it in your block
;; ...
the-url (-> (url "http://example.com" "subscribe")
            (assoc-in [:query :param] "a param")
            (add-location options))

ClojureScript - 在 go 块中有条件地构造 url

ClojureScript - construct url conditionally in go block

url

asynchronous

clojure