当试图支持clojurescript中的跨浏览器前缀时，“未捕获的TypeError:非法调用”

Question

getUserMedia有许多前缀，在许多浏览器中仍然是必需的。我试图通过在getUserMedia中放置所有前缀来隐藏这些前缀的使用。

(def getUserMedia
  (or js/navigator.getUserMedia
      js/navigator.webkitGetUserMedia
      js/navigator.mozGetUserMedia
      js/navigator.msGetUserMedia))

(defn start-fx [app]
  (if getUserMedia
    (getUserMedia 
     ;; WORKS IF I REPLACE THE ABOVE getUserMedia WITH
     ;; js/navigator.webkitGetUserMedia USING CHROME BROWSER
     #js {:video true :audio true}
     #(om/update! app :record-src (.createObjectURL js/window.URL %))
     #(throw %))
    (js/alert "This browser does not support video recording!")))

然后，当我试图从start-fx调用它时，在调用getUserMedia时会得到一个Uncaught TypeError: Illegal invocation。我应该怎么做才能允许代码跨浏览器兼容？

Answer 1

getUserMedia必须绑定到navigator对象。对应的JavaScript应该是：

var getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia ||
                   navigator.mozGetUserMedia || msGetUserMedia;
if (getUserMedia) {
  getUserMedia = getUserMedia.bind(navigator);
}

Answer 2

为了得到一个答案，我发布了我的解决办法。肯定有更好的解决办法吗？

(def getUserMedia
  (or js/navigator.getUserMedia
      js/navigator.webkitGetUserMedia
      js/navigator.mozGetUserMedia
      js/navigator.msGetUserMedia))

(defn start-fx [app]
  (if getUserMedia
    (let [[c s f] [#js {:video true :audio true}
                   #(om/update! app 
                               :record-src 
                               (.createObjectURL js/window.URL %))
                   #(throw %)]]
      (getUserMedia c s f))
    (js/alert "This browser does not support video recording!")))