Add documentation on setting up react native app about docs

[Peter-ChengTszTung]

cc @louischan-oursky
Notes for RN iOS:

Prerequisites

• Enable Authgear OAuth Feature

Setup

• Install @authgear/react-native and @react-native-community/async-storage packages

  yarn add @authgear/react-native -S
  yarn add @react-native-community/async-storage -S
  

  cd ios
  pod install
  

• Add a URL scheme to your iOS project (iOS 10 or below)

  • Open ios/{project}.xcworkspace
  • Under {project} -> {target} -> info tab -> URL types section
  • Press '+' button
  • TBC

• Setup UIApplicationDelegate with AGAuthgearReactNative bridge

  • Open ios/{project}.xcworkspace
  • Under AppDelegate.m, add

    ...
    #import <authgear-react-native/AGAuthgearReactNative.h>
    ...
    - (BOOL)application:(UIApplication *)app
                openURL:(NSURL *)url
                options:
                    (NSDictionary<UIApplicationOpenURLOptionsKey, id> *)options {
        return [AGAuthgearReactNative application:app openURL:url options:options];
    }
    
    - (BOOL)application:(UIApplication *)application
                  openURL:(NSURL *)url
        sourceApplication:(NSString *)sourceApplication
              annotation:(id)annotation {
        return [AGAuthgearReactNative application:application
                                          openURL:url
                                sourceApplication:sourceApplication
                                      annotation:annotation];
    }
    
    - (BOOL)application:(UIApplication *)application
        continueUserActivity:(NSUserActivity *)userActivity
          restorationHandler:
              (void (^)(NSArray<id<UIUserActivityRestoring>> *_Nullable))
                  restorationHandler {
        return [AGAuthgearReactNative application:application
                            continueUserActivity:userActivity
                              restorationHandler:restorationHandler];
    }

Get Started

const container = new ReactNativeContainer();
container.configure({
  clientID: '{client_id}',
  endpoint: 'https://localhost:3000',
});

const authorizeOptions = {
  redirectURI: {redirect_uri}
};

const authResponse = await container.authorize(authorizeOptions);
console.log(authResponse.userInfo);

[Peter-ChengTszTung]

@louischan-oursky
Notes:

• iOS 11 or above: No need to setup URL scheme and app delegate

• iOS 10: application:openURL:options: and application:continueUserActivity:restorationHandler:

• iOS 9: application:openURL:sourceApplication:annotation: and application:continueUserActivity:restorationHandler:

• React native 0.63 drop iOS 9 support

[louischan-oursky]

iOS 11 or above: No need to setup URL scheme and app delegate

Any details?