Fix race condition in deep linking

lib/platforms/react-native.js

@@ -1,21 +1,32 @@
 import { Linking } from 'react-native'; // eslint-disable-line import/no-unresolved, max-len
 
-export const dance = authUrl => Linking.openURL(authUrl)
-  .then(() => new Promise((resolve, reject) => {
-    const handleUrl = (url) => {
-      if (!url || url.indexOf('fail') > -1) {
-        reject(url);
-      } else {
-        resolve(url);
-      }
-    };
+let previousOnLinkChange;
 
-    const onLinkChange = ({ url }) => {
-      Linking.removeEventListener('url', onLinkChange);
-      handleUrl(url);
-    };
+export const dance = (authUrl) => {
+  if (previousOnLinkChange) {
+    Linking.removeEventListener('url', previousOnLinkChange);
+  }
 
-    Linking.addEventListener('url', onLinkChange);
-  }));
+  return Linking.openURL(authUrl)
+    .then(() => new Promise((resolve, reject) => {
+      const handleUrl = (url) => {
+        if (!url || url.indexOf('fail') > -1) {
+          reject(url);
+        } else {
+          resolve(url);
+        }
+      };
+
+      const onLinkChange = ({ url }) => {
+        Linking.removeEventListener('url', onLinkChange);
+        previousOnLinkChange = undefined;
+        handleUrl(url);
+      };
+
+      Linking.addEventListener('url', onLinkChange);
+
+      previousOnLinkChange = onLinkChange;
+    }));
+};
 
 export const request = fetch;