[RN] Add a timeout for loading the configuration

react/features/base/util/loadScript.native.js

@@ -1,3 +1,7 @@
+// @flow
+
+import { timeoutPromise } from './timeoutPromise';
+
 /**
  * Loads a script from a specific URL. React Native cannot load a JS
  * file/resource/URL via a <script> HTML element, so the implementation
@@ -6,9 +10,12 @@
  *
  * @param {string} url - The absolute URL from which the script is to be
  * (down)loaded.
+ * @param {number} [timeout] - The timeout in millisecnods after which the
+ * loading of the specified {@code url} is to be aborted/rejected (if not
+ * settled yet).
  * @returns {void}
  */
-export function loadScript(url) {
+export function loadScript(url: string, timeout: ?number): Promise<void> {
     return new Promise((resolve, reject) => {
         // XXX The implementation of fetch on Android will throw an Exception on
         // the Java side which will break the app if the URL is invalid (which
@@ -26,7 +33,31 @@ export function loadScript(url) {
             return;
         }
 
-        fetch(url, { method: 'GET' })
+        let fetch_ = fetch(url, { method: 'GET' });
+
+        // The implementation of fetch provided by react-native is based on
+        // XMLHttpRequest. Which defines timeout as an unsigned long with
+        // default value 0, which means there is no timeout.
+        if (timeout) {
+            // FIXME I don't like the approach with timeoutPromise because:
+            //
+            // * It merely abandons the underlying XHR and, consequently, opens
+            //   us to potential issues with NetworkActivityIndicator which
+            //   tracks XHRs.
+            //
+            // * @paweldomas also reported that timeouts seem to be respected by
+            //   the XHR implementation on iOS. Given that we have
+            //   implementation of loadScript based on fetch and XHR (in an
+            //   earlier revision), I don't see why we're not using an XHR
+            //   directly on iOS.
+            //
+            // * The approach of timeoutPromise I found on the Internet is to
+            //   directly use XHR instead of fetch and abort the XHR on timeout.
+            //   Which may deal with the NetworkActivityIndicator at least.
+            fetch_ = timeoutPromise(fetch_, timeout);
+        }
+
+        fetch_
             .then(response => {
                 switch (response.status) {
                 case 200: